Mexicans are friendly, polite and supportive. When I first told people I was coming here they gave me grave warnings about getting kidnapped or worse, having sellers try to sell me stuff! and I must admit, after doing the 'love boat cruise' a few years ago and being guided into the tourist traps at the ports, I was afraid of being singled out as the tall, white walking US dollar bill, that attracted all the local very eater and persistent sellers within a hundred metre radius. But here in Cancun, I can say I have had no problems at all, it's been wonderful. I have seen two sellers on the beach in front of the hotel, but if looking at the number of teenaged braided heads and small straw hats on the tourists was any indication, they were doing a great trade and they did not impose. The sea here is magnificent and the climate is divine.
Would I recommend Cancun? I certainly would. All is well.