I had a simple U-shaped handle installed in the middle of the door, and at night inserted a 3/4" dowel through it. The dowel was about 4 feet long, long enough to sit strongly against both side of the door frame.
As well, I keep my car key near-by during the night; it's emergency alarm would give notice that I'm being bothered.
I also put out TWO lawn chairs.
I did NOT stay in remote areas, and if I was paying, I asked the attendant to put me near other people. At Wal-mart, I always parked close to others.
BTW, was never bothered in 3 months of travel, whether in a Wal-mart parking lot, or a well-attended camp ground.
Paranoid? No. Prudent? Yes.
Originally Posted by Roy in TO
Ours has a toggle lever on it. If you flip the toggle, it locks the door from the outside but it will still open from the inside. You will need 2 people to test yours. One inside, one outside.