while riding up on the train from cuzco to macchu pichu, i met two backpackers from sweden with a horrible story to tell: they'd just arrived in town, near the end of their 3-month trip across south america, and were in the main square with their backpacks when they decided to catch a taxi to their hostel. being the careful backpackers they were, they flagged down a somewhat-official looking taxi (numbers painted on the side of the doors, but no company sign on top) in the plaza de armas.
instead of taking them to their hostel, the driver took them to an quiet part of town far away from the center. several men with guns then got into the taxi, and ordered the women to give them everything from their pockets, in addition to stealing the backpacks, and finally frisked them for anything else. the girls were then shoved out of the taxi in yet another part of town, and luckily escaped with their lives and without being physically assaulted.
i know there are some backpackers who cruise around the world with false stories like these, in order to try and sponge off of other backpackers, but these girls seemed definitely on the level. i ended up letting them use my digital camera on the mountain (since theirs was stolen), and then let them burn them to CD when we'd returned to the city, so at least they were able to get photos made of the last part of their trip.
anyways, just wanted to pass this one along. watch out (especially in cuzco) for taxis without an actual taxi company's sign on top of the taxi. losing all of your gear is pretty much the last thing you want to have happen to you when travelling.