I no longer work, so I rarely carry a pen. But when I was working, I'd cringe when some ill-prepared fool would ask to borrow my pen.
First off, people are gross. I don't want someone's booger remnants on my writing tool. Then covid came around, and I was vindicated.
Secondly, my pen costs more than many people's good knives. I don't want a goofball jamming up the tip. Invariably, if I loaned them my pen, they'd be all, "Urrrrgh... umphh... mmfff... Isn't this what John Hancock used to sign the Declaration of Independence? I don't think it works... How to you write with one of these?"
I guess fountain pens and locking knives just aren't for everyone. Luckily, I never had anyone stab themselves with one of my pens.
To me, asking to borrow my knife is like asking to borrow my gun. Asking to borrow my pen is like asking to borrow my underwear. You'd better be a really good friend before trying either.