When I saw this thread initially, I really thought it might be a joke. The thought of a couple of guys trying to sell an air conditioner out of the back of their car is just too bizarre. Then I remembered an interview I had heard, probably on NPR, about the upsurge in crime of people stealing heavy equipment from construction sites. (PSST... Buddy... can I interest you in a nice D-9?). So, yeah, I guess nothing is safe. And had it happened to me, I would feel just incredibly violated.
The closest I can come to wrapping my mind around this is how frustrating it is to have a bear break into a cabin. One trick I have heard of recently involves coating cans of bear spray with bacon grease, and leaving them hanging near the door. The bear bites it and doesn't come back. Can you think of some variation on this?