I used to think this, too, until I served on a jury for a trial in which a man was accused of breaking and entering. There was a question as to whether or not the door of the victim was locked. The judge instructed the jury that it doesn't matter if the door was locked or unlocked - it is considered breaking and entering if you open the door and walk inside of private property which you do not have permission to be in.
Maybe, in the long run, if it comes to the court.
But, locking *any* door will deter a lot of people, because it takes a little more effort than just opening the door and walking in. The majority of crooks would rather not make a *scene* if possible. They prefer easy pickings. (Hence, most go to the backs of homes to *break* in).
It may have happened, but I've, personally, never heard of a *break in* at the Disney campsites. Leaving a door unlocked is like an *invitation* to a thief IMO. We need to do whatever is possible to keep our belongings safe - lock bikes, keep things close together near center of site, don't make things so visible that someone could just *pick up*.
I've seen some sites with things, toys, bikes, whatever, all over the place, and people have left and gone to the parks (or wherever, not there). Makes me wonder what their homes look like.
