In general I've found campers to be more courteous and less likely to take something than the general population. My folks, brothers and I have been camping since 1950. Between my folks and 3 brothers and I none of us has ever had anything taken from a campsite. Daughters InLaws have been camping since the 60's and did have one time when they lost some bacon out of the cooler.
Well, actually we have lost somethings, a few packages of peanuts or snacks more than once have had squirrels get into them.
We are reasonably carefull, but usually, chairs, coolers etc. are left outside day and night and never have had a problem. We do usually lock bikes up at night