i don't think they can just stay there but i'm notsure...... we seen a few ppl walking though last year... as we did with the other resorts... we walked down the beach just to go for a walk and see what the other resorts looked like......
All beaches in Mexico are public there by anyone can walk by and if they are not trying to sell things can generally linger by staying off resort items like loungers.
Xmas /NY week there were kids playing on the beach for a couple of days. May have been staying on one of the big yachts at the marina. They didn't bother anyone. There were no panhandlers or beggers, but a few merchants (sun dresses ect)would walk through but all transactions had to be done off to the sides of TTR The beach is beautiful , and the water is nice for 40 to 50 feet and shallow, then your into weeds
When we were there security were very good, they followed any dubious looking people on the beach! We saw kids too, but they didn't hang around for long, I think the mother dragged the husband away for staring at all the women!!!