When I was younger (and before I got into fountain pens), I knew a lot of people who worked in the restaurant industry, and being on the wait-staff pretty much means you are a black vortex that sucks in pens never to be seen again. I also was a student, which similarly means that pens would get sucked up.

I've always liked certain pens, and it drove me wild when I'd lend my pen for a moment and then get "Oh, sorry, a customer stole it", "It's in my other bag", or "I lost it", the next day. So I started keeping around a box of BICs around for that purpose. Way less stress to just keep a few sacrificial pens around.}

With fountain pens? I don't even let people handle those for more than a moment. I still keep a few pens from the zip-lock bag full of old ball-points that people are more welcome to borrow from.