I just came back from a trip to Chetumal. I didn't have any problems, but being aware of the warning, I made a note of the taxi number, which is posted on the car door before getting in. Also, I made sure that the taxi driver got out of the vehicle to remove my bags. Most of the cases I heard about were from people who had paid the driver, gotten out, and went to get their bags form a back seat and the driver took off. Also, I have heard about drivers taking people to remote locations and robbing them. I am a little bit familiar with Chetumal so I kept my eyes open to make sure they were staying on the appropriate route. All in all, being aware, not flashing cash, not looking affluent. I also did another "trick" that I have used several times in the past. I would have a fake phone conversation, and say the cab number IN SPANISH to make the driver think I was in communication with someone, who knew my whereabouts. It didn't matter that I couldn't get a signal, they didn't know that.