My local Home Depot installed those self-serve lines. I was one of the first to use them one morning when I bought some goodies for about $53. I put cash in and my change was supposed to be something like $17. the machine spit out about $92 in cash and a few coins. There were guys in ties watching the process so I told them that these machines are great, I'll definitely shop here more often. They were all smiles until I flashed my extra cash and told them what had happened. Their smiles dropped.
Apparently someone had put the bills into the wrong trays in the machine.