I mean, it's also an anti-pattern with wallets if you hand them your wallet full of cash and tell them to take a tip. A PIN is not a bad idea though.

I think this might be an actual generational difference; I feel weird letting someone else use my phone or using someone else's phone now. I can remember a time when phones were much more communal - the family shared a phone, and public phones existed, and I wonder if older folks are a bit more locked into that way of thinking. Obviously a phone is much more than a phone now however.