Oddly enough, I have found people to be very respectful of other people's towels and spots/chairs at TL. I do recommend, though, that you buy one of those necklace boxes (they seal out water) to store your $, tickets, etc. They work perfectly (some resorts have them; CBR had them with their logo on them for $6).
Also, Fuji's waterproof camera took great pictures even after dangling underwater in the river for two hours while I floated.