I really don't want to offend anyone, but the situation this year has officially gotten out of hand. Leaving items on the beach is illegal, but deputies are lazy and/or have other things to do. Their boss is not on them about bothering people who visit and spend money.
It's quickly becoming apparent that it is up to residents to educate visitors and possibly form patrols to help keep the beaches clean and safe. The beach service guys I'm sure would delight in spreading the word as it would be good for their business and they would get to vent their frustrations.
No one has anything against anyone else having fun, being comfortable, and relaxing. But there are just too many people enjoying our beaches now and something's got to give. Tents on the beach, along with all the stuff that comes with them, have gotten to be a real nuisance. Not only for the reason mentioned regarding the rude act of "reserving" spots, but for many other reasons too. Beach camps have become eyesores and dangerous. It is an extreme form of littering.
It has to come down to sensitivity and politeness. Ask yourself "what if everyone did it"? It would be quite a mess and we're getting to that point. If you don't understand that it is the wrong thing to do, then the majority of residents and visitors would like you to find another vacation spot.