Also, I was advised to back the trailer into a spot, preferably against a wall. They'll have to also steal your vehicle that way, or figure out how to get it out of the way.
I traveled from Bellingham, WA to Nashville, TN in a squareback VW loaded to the rafters with stuff. I did the back-in technique, and had no trouble. That was a long time ago, and I stayed at Best Westerns all the way.