Anywhere there's a lot of foreign tourists and local unemployment, you'll find them: local people who seem smart and speak English, yet inexplicably have nothing better to do than talk to you.
I hate to paint with a broad brush, because in every country, most of the time, I've also had fantastic experiences with locals who legitimately want to talk to you, practice their English, or make some foreign friends. But it's important to always stay aware of your surroundings, and remember that context is crucial. The stories below -- my own and others' -- are illustrative of the precautions you should take, especially in tourist hubs.
Argentina and Italy: Mustard Attack
This blog post is what reminded me to write about common scams. This one is straightforward: in a public area, one person distracts you by spilling some kind of liquid on your clothes; a second confederate pushily offers to help clean it off, while a third takes advantage of the distraction to steal your loose bags. In addition to this report from Rome (incidentally, the only city where a pickpocket tried to steal my wallet, unsurprisingly on bus 64), I have also heard of this happening in Buenos Aires. Both cities have a reputation for lax police forces and high unemployment, not to mention hordes of oblivious tourists.
The lessons outlined in that blog post are good: if you're attacked, get away from the team, stay in a public space, and never let go of your bags. As a rule, when I have my backpack on, I try to keep my back to the wall whenever I'm not moving.
Thailand: A Better Bus
This isn't a complete scam, more of an annoyance. There's lots of scams in Thailand, especially around Bangkok. But, in this case, you will get at least some of what you're promised.
Basically, a lot of local transport in Thailand is accomplished through songthaews, which are somewhere in between a shared taxi and a regular bus route. They're pretty convenient, if horrifically unsafe (and generally run by local mafias that shut out any improvements in transport infrastructure). There's often an overabundance of drivers, and they get paid a set rate -- often posted on the taxi. This is again, pretty convenient and nice.
The problem comes when the drivers want to make some extra money. For instance, I was riding from the city of Trat to the ferry port on my way to the island of Ko Chang. The official ferry ticket office -- with the cheapest ticket prices and no fake tickets -- is at the port. However, my songthaew driver felt the need to top twice on the way to tell me and a French expat also riding (who thankfully was a local, and would argue with him) that "you buy your ferry ticket here." After telling him "no" twice, we finally arrived at the port, where three more ticket agents were waiting to intercept us. The Frenchman practically sprinted to the official ticket office, running a gauntlet of a few more ticket-sellers, and I followed right behind him.
Likewise, coming back from Ko Chang, there's several different ferries, but only one of them is a safe, new ship. I knew for a fact that my ferry terminal was the last stop on the songthaew route. On the stop before, a woman was allowed to hop on board and try to sell us a package ferry ticket -- on the old, dangerous ferry -- that would connect to an "air conditioned VIP" bus on the mainland to take us to Bangkok.
Now, I had done my research, and I knew from many warnings in the Lonely Planet that this "VIP" bus was probably a van with no air-conditioning that would leave when it was full, not when the ferry got to the dock. The driver would likely drive extremely dangerously as well. I also knew from the Lonely Planet that there was a Thai government-run coach bus waiting to depart from the good ferry port as soon as I arrived there. The Thai government bus company runs fantastic buses, with ridiculous air conditioning, toilets, and even a "flight attendant," for basically the same price as these "VIP" buses. So, after telling the woman "no" five times, the songthaew driver gave up and we went onward to the ferry port. The group of backpackers traveling with me in the truck, however, had not done their research and got off with the woman. They probably got back to Bangkok in the end, but they weren't half as comfortable as I was and ended up spending more money. The moral of the story is to do your research. Most parts of Thailand are extremely well-traveled now, and the Lonely Planet knows what it's talking about. The Thai government knows that tourism is an important source of revenue, and makes efforts to make tourists' lives easier: take advantage of them. And remember that the drivers aren't honest, but they aren't dishonest either; they operate within a set of rules that isn't immediately obvious -- their prices are fixed, but the bosses turn a blind eye to this kind of revenue-raising.
Beijing's Art Students
This is another scam that I've encountered myself. It's annoying, to say the least. If you're visiting a major tourist destination in Beijing, especially the Forbidden City, young Chinese will introduce themselves to you as "art students," perhaps flashing some sort of ID card that you can't read in an attempt to gain trust. They will say that there is a "special exhibition" happening today, and they would really like it if some foreign visitors came and viewed their art. Needless to say, if you go with them, you will be pressured into buying overpriced pieces of knockoff art; they will make it uncomfortable for you to leave without buying something.
Because the Forbidden City is quite expensive to enter, I suspect that they have some sort of corrupt bargain to get in -- and the fact that they're inside the walls gives them an air of legitimacy. However, I do not know where the "special" art shows are, only that this scam happens constantly enough to merit mention in the Lonely Planet, along with a related scam where attractive young women convince foreign men to come observe tea ceremonies; after the ceremony is over, bouncers make it clear that the men cannot leave until they pay hundreds of dollars for the ceremony. This, in a country where magnificent banquets can be had for tens of dollars at the most.
I must emphasize, however, that these scams are limited to a few areas with many tourists. Outside of Beijing and Shanghai, I had nothing but good experiences with the many young Chinese people who wanted to say hello or practice their English. Likewise with other countries.
However, the best thing to do is continue moving until you're fairly certain of someone's intentions. Once you've stopped walking, you have committed to a conversation, and it will be much more difficult to get out. Once you've stopped walking, you're exposing yourself to bag theft as well.
Trapped in Italy
Here's one scam that hit close to the heart. I was in a train station in northern Italy when a man with a backpack asked, "Excuse me, do you speak English?" He was clearly not a native speaker, but I wasn't sure where he was from. He flashed a computer printout at me, saying that it was his train ticket and he had missed his train. He had no money (I forget why, perhaps pickpocketed?) and was trying to raise enough money to get to his destination, where his friend was waiting. When I said "no," he got more angry and abusive, at which point I moved to a different part of the station. Leaving to catch my train some time later, I spotted him making the same pitch to some other travelers.
Under ordinary circumstances, I might have been willing to toss a Euro his way. All travelers survive on the kindness of strangers -- and who knows, the story was superficially plausible. But I couldn't get to my wallet and get out a coin without giving him ample time to grab it all and run. With my heavy backpack, I never would be able to catch him. The experience made me consider keeping a few loose Euro coins in my pocket.
More importantly, though, I had to be cautious that he didn't have any confederates working with him. During our conversation, I made sure to keep my back (and my backpack zippers) close to the wall, so that no-one could sneak up behind me. As with the mustard bandits above, this is a real concern. I also knew when to walk away.
That Guy from Your Tunisian Hotel
I have to end with a blindingly stupid line that I encountered several times in Tunisia. In a way, it led to the one time I was robbed while traveling -- a story for another time.
On this occasion, though, I had just spent a few days living aboard an acquaintance's sailboat that was docked in Monastir's harbor. I was walking through the old city center on my way to the train station; the train would take me to Tunis and, shortly, to the UK. A man about my age called out to me in English.
He asked, "do you remember me?"
Well, no, I didn't.
"I worked at your hotel. Remember, I was one of the waiters?"
"Well," I said, knowing full well that I hadn't been in a hotel in four days, "which hotel was this?"
"Which hotel do you stay at?"
Lucky for me, I was in fact going to the train station, and I didn't have to invent any destination when he asked where I was going, suggesting that we should hang out. And that's the most transparent con that I've come across in all my travels; it's so transparent that I wonder whether they expect it to work. On the other hand, Monastir was the same city where some bored youths called out to me from the opposite side of the street, "Hey, American! Give me some money!" (Maybe if they spent their time finding or making work... well, with the Tunisian revolution that has since happened, maybe there will be more job opportunities for youth).
In any case, it's better than being mugged. But it's still annoying. The root causes that put scammers on the street are many -- good education combined with high unemployment, uninterested law enforcement, and the less cohesive communities inherent in large urban areas (as opposed to rural villages and small towns) would seem to make up much of the combination. But the fact is that the scams pay well enough to keep the scammers in business -- so stay smart, and don't give them any business!