I drove to sell a ski on an open uhaul trailer. It was a long enough drive to justify staying at a hotel. I didn't think ahead enough to worry about theft, and it was only a $3000 superjet. Once I got to the hotel I started worrying about theft - I wasn't selling the ski until the next morning. My thought was either park it under bright lights, or back it into the darkness. I chose the latter.
On top of all this, Uhaul trailers have a clamping mechanism to allow for either 1-7/8 ball or 2" ball. Anybody can disconnect it and steal the entire trailer by pushing down the tab and unscrewing the clamp. I don't see any way to put a lock on this. Then I'd be charged by uhaul to replace the entire trailer on top of losing my ski.
After some thought I decided to drive to the nearest bar (very rural area), pound down a few beers outside while watching the ski, socializing with the locals (I told them it wasn't worth much) and drove my two minute drive back to the hotel at about 3am. I said a prayer, went to bed and thankfully it was still there the next morning.
Everybody beware the ease of disconnecting uhaul trailers.