I don't lend my knives out a lot. My father is the one who borrows them more often, but when he says "Have you got a knife?", what he means is "Let me see your new toy.", he always has a knife on him.
My brother is a similar case, but it has become less common as his own knife collection grows.
My girlfriend has a few knives of her own, but she doesn't pocket carry (she uses her purse) so they aren't always as handy as mine, she usually just asks me to cut whatever needs cutting, she knows I love using my sharp and ponties!
With other people I always ask what they intend to do with the knife, if it's nothing crazy and I trust them I'll lend them my knife or a SAK if I'm carrying something that's too pricey for sheeple.