I rarely ever shoot at ranges where I'm in the company of people I don't know, so, anyone shooting my guns is someone I already know, or they've been vetted in advance.
If some random person did express interest, I'd probably let them shoot a mag- or cylinder-full, but it would have to be after more than a little discussion, when I would have a chance to size them up, first.
Something along the lines of, "D*mn, that's loud, can I have a go?" probably wouldn't do it.
If it were more like, "Hi, my dad had a Luger, I remember handling it as a kid, but was never able to shoot it; do you mind . . .", then, after watching how he handled the gun while we discussed it, I'd probably feel good about letting him shoot it.