“When was the last time another guy, previously unknown to you, bought you a beer?”
Happens all the time in private clubs, about every time you go.
Back in my youth I used to go out to bars all the time - 4, 5 nights a week for a stretch.
I have never been bought a beer by a guy I didn’t know EXCEPT in the context of him buying beers for a group of people where I was one of them.
I would find it exceedingly strange and an extraordinary circumstance to have another man buy a beer for me.