Crime is almost non existent in the hotel zone. Cancun is very dependent on tourism and there are extreme punishments for even petty crimes. The local thugs know it and it's a huge deterrent that very effectively minimizes and prevents crime. Are there isolated incidents? Of course, but overall I find CUN to be an extremely safe layover and I have adventured all over that place at all hours of the night including downtown. Never a worry or nervous moment.