I've never heard of theft in a campground. Perhaps a chair or something else of interest, but never a break-in or total theft of TT at a campground.
We had our HTT stored at a storage lot for about 6 months when it was broken in to. I only had the door lock on, not the deadbolt. I didn't think it needed it. Nothing was stolen, they just busted the lock. I put the dead bolt on and a week later they tried to break in again. They couldn't get the door open, so they broke the window in the door and even ripped the door skin a couple inches. The police thought they were probably just looking for a place to sleep. I thought that odd since it happened at the end of April after a really cold winter (cold for SE, Coastal GA anyway). Just out of spite, they broke the hitch pin lock, but it did not appear they tried to actually hitch up.
I noticed that the only other TT in the lot had also been broken into. That TT had a coupler lock, which the suspect also cut off. Not sure why, maybe they thought the same person owned it. That storage lot had no exposure. Someone could have broken in to any of the vehicles in storage without anyone noticing.
We moved the HTT to the backyard for about 15 months, the HOA doesn't allow it, but only person owner could see it and he didn't complain. We moved it to another storage lot with a lot more exposure and cameras on the outside storage area. Never had a problem there in the almost 6 years we stored our HTT and then Motorhome there.
Probably one of the most stolen items are batteries in storage. We always pulled ours off the tongue along with the propane tanks. After the initial break-in, we always kept the deadbolt locked when in storage. Since it was a Hybrid, we always locked all three beds.
-Michael