I made reservations for the Wild Tours ATV/Kayak/Snorkle excursion in Cozumel. I want to know whether it's ok to wear flip flops or should we wear tennis shoes. I read that you should wear things you don't mind getting dirty. For the sake of packing I'd like to only bring my workout tennis shoes... Will I be OK w/flip flops, or might that be dangerous on the ATV's w/no foot protection? Anyone have experience with this?