Been on the recieving end twice.
Once saw my suitcase disappearing out of the terminal at Dubai, just good fortune I was in the right place. Guy claimed he mistook it (somewhat difficult as the unique nature of what it was and the tags I had on it).
Other time I picked my own bag up at Heathrow T1 only for a large chap to half slap half push me on the back demanding I give him his bag back (it happened to be mine)