If I thought someone was going to crash one of my bikes, I certainly wouldn't let them ride them. I like them far too much to risk that. I also have a lot of time and money invested so I make damn well sure that whomever is riding one knows what they are doing.
With that said, I let me girlfriend ride one of my bikes while it was still in "test" mode. Basically I didn't have the throttle cable hooked up perfectly, so when you twisted the throttle it wouldn't engage until it was almost twisted all the way. Long story short, she popped 3 wheelies in about 15 feet, turned around and brought it straight back to me. It was pretty funny, but she was a little gun shy after the fact. Now the bike is dialed in and she rides it like a champ.