[Transit]

Yes, all the time actually.
With a few caveat, naturally- first I put the strap around their neck, so I'm ensure that if they let go of the camera that it's not going anywhere, then I give them a really quick lesson on how the camera is configured (look though the diopter, how to adjust the diopter, and how the focus is setup).
Then I relax, and enjoy being in the shot.
..........

100% same here. Heck, they might even buy into Pentax as a result

[TER-OR]

It did scare her, though, since I had it on continuous high drive. I'm accustomed to using a light touch, but she mashed down the trigger after the half-press and it fired of 5 shots before she knew what hit her. Her little shriek was amusing.

[kadajawi]

Self timer on a tripod? Or remote? Also tell them that your camera is not set up for use by others than you, it doesn't work automatically and requires an experienced photographer to operate. The P&S also seems like a fine option.

Personally, if I am around I am fine with it, if the right lens is mounted. Put it into the green mode and enjoy the confused looks (you mean I have to look through this?). But I can totally understand you, and I wouldn't lend out my camera except to a few people perhaps, and there I know they have the money and the morals to compensate me if necessary. I'm sure I could have a go at their gear too. So there, fine.

I have indeed borrowed gear a couple of times, for example when my trusty old Pentax wouldn't work anymore and I needed something for a shoot. Though those were an old cheap Sony DSLR and a Nikon D40s, so nothing precious, and a GoPro 2 and Sony NEX 5 for a video shoot to get more angles during a concert (the singer was the owner of those cameras).