Yap just got back from Cancun mexico myself and few years ago we went to cuzeml and I dove in both places beautyful place to dive if you like you can view my dive pictures at cancun on myspce it is epetroisan10 my name and go topics you see the dive pics. only thing is eat at your resort dont worry about anything in diving wise. "Dont drink water outside your resort". carry bottle water or buy gatorate and avoid those hole in the wall resturants. you friend might of been a very icelated incident. look at my dive pic I am in shorts and one other diver is not even wearing a suit. Enjoy your time dont panic if you have any questions ask on myspace.