I've had two bikes totalled while being ridden by friends.
One was an ST2, which I mourned the loss of. His insurance bought it, but paid under book value by about $1,000 (Progressive). I wasn't stoked about that part.
Another was a ZZR1200 which was still in test ride mode - so the guy bought it and fixed her up - not a big deal.
I'm a little more reluctant to lend out a bike now, but I still don't mind if I've ridden with the person and I know how they ride. At the end of the day, it's a risk and the question is whether you trust the person to make right any mistake they might make.