Or, "A guitar is like a toothbrush. You only stick it up your ass and give it back to the owner if you dislike that person." I echo Austin's sentiment. I let other people play my guitars at my jams all the time; as long as they're in my sight, I'm cool with it. I prefer that people I don't know play my Strats and not my Hamers, though. Currently my Cruisebass is on indefinite loan to my bass player, because he loves it so. He's welcome to play the shit out of it; I trust him, and I don't mind if he relics it up a bit.