Loaner knives? Absolutely not. I do not loan my knives (or tools) to anyone, much less someone who I either don't know, or do know and know they aren't knife people. I have no issue telling someone "Sorry, can't help you" right to their face, even after they've pointed out the pocket clip sticking to my pocket. Not trying to sound mean or like a tough guy, I'm just an adult who sets consistent boundaries* and I'm not going to let someone else abuse the fine tools I carry.
That said, I have been known to ask to be shown what needs cutting, and if it's something non-abusive, I'll do it. That's as far as it goes, though.
* Something that most people frown on others doing, especially when it inconveniences them.