Never had anybody steal anything, or think about stealing anything, but I took a gig years ago for some friends and they paid me in the bassists old rig that he left behind and since he refused to answer their phone calls and he fell off the face of the earth I do not think he is missing them.
I also bought a Marshall combo for $40 since it was left at buddy's house and the guy who left it owed him money and refused to answer his calls, I paid the $40 he was owed and took the amp home with me.
A drummer friend of mine used to jam with some guys he worked with, they quit that job and disappeared and the drummer couldn't contact them for months. This went on until he had a week to move, once he moved with the stuff there was really no way for them to find him and he had tried and given up on finding them. They ended up calling him 2 days before he moved out of the blue and came to get their gear.