When I was working for Kitty Hawk Air Cargo, we had a guy fall asleep in the aft bin on a 727 heading for PDX and GEG.
Since the aft bin was "empty", the PDX staff did not even open it and so the guy flew on the GEG.
Needless to say, he was fired when he got back to MHR.

It is possible to open the bins on a 727 from the inside so it's a good thing he didn't try it while in the air.