Here are some simple rules for traveling:
At night, do not leave your walet or camera near a screen window, if your room has one.
Do not leave your wallet or camera on the beach, even if its wrapped up in a towel and you're snorkeling right in front of it.
When you leave your hotel room, do not leave cash or cameras in plain site.
Always lock your door, no matter what.
Do not give any cigarettes or free beers to the local boys, you'll be stuck with them for the remainder of your trip (oh oh, I know this comment will get me into trouble now)
Use the same rules here as you would anywhere and you'll be fine.
Caye Caulker has almost as many police officers on this little island as they do in all of San Pedro. They even have a special branch that is specifically trained for tourists.

C'mon,

i admit that i am not a local so i can't pretend to be a expert. but from my time as a single gal on the island, the attention one gets from the "nasty" (that would not my word choice) beach boys is not offensive and you decide what your interactions with these guys will be. even though i work(ed) in tourism, i never felt the need to caution woman about their personal safety (as long as they are making smart decisions) with these guys - only that they should keep their hearts in a safe place.