I'll second that... No Lockers.
At the same time, there are also a lot of people around, so I think the odds of stuff getting stolen are pretty small. Yes, it's a possibility, but at long as you don't advertise the fact that you have any expensive items with you, you most likely will not have a problem. An yes, I've taken expensive cameras to CC and left it in our bad on the beach while we all went snorkelling.
If you still feel real insecure about it, perhaps you can attempt to lock it to something that is semi-permanent. If you can get a spot under an unbrella, they are pretty much fixed in place. I'm sure that there is some easy way for them to be removed, but if someone was willing to go that far to steal something, it seems like it would help draw attention to the situation. Just a though.