I remember finding a bot in WoW who was set to run a curcuit and kill, then skin some creatures (basically letting the person gather a lot of materials [expensive materials] while they weren't actually playing). I took great delight in following them around and skinning things before they got to skin them. I also camped another bot doing the same thing but from the opposing faction. Kill, hide, wait for it to return and res, kill, repeat... I think I eventually broke it because it stopped coming back even after factoring in respawn timers.