Put a Lo Jack on 'em!
Back in the early '90's I played at the famous rock club CBGB's in NYC. At a club like that they have bands every 45 min from 8 pm til 2 am. It's chaotic. A band is loading in while one is loading out. The catch is, if you want to play for a empty house but get the record execs there you go on at 8. If you want a packed house, you play late. Well we wanted the record eecs so we played first at 8pm. After the set a few execs from Polydor and Capitol took us out on the town. We left NYC around 4 am. When we got home to Pittsburgh later that afternoon I discovered my Kramer Pacer that was signed by Joe Satriani, Alan Holdsworth, Pat Metheny and Ted Nugent wasn't in the van.
I figured there would be no way on earth that my guitar survived 4 bands loading in and out after us in New York. I called the club and asked if by some miracle a guitar in a blue gig bag was any where around. Sure enough it was still sitting beside the back stage door!!!
Either no one wanted it or there were some honest musicians there that night. There's a little hope for humanity but my iPod was stolen last weekend 
One time when I was 17 I left my Les Paul 'Special 57 reissue in a parking lot after a gig forgetting to put it in my car. I got home, realized it wasn't there, drove back to the club and there it was ...sitting all alone in the parking lot. And I wasn't even drinking!!!
Come to think of it, I don't have any of my guitars serial #'s registered. I need to do that tonight!
Hope to see you soon Joe!!! 
Cathy