<human>: Asking for a guy friend. I myself am 33/f. I've had to deal with enough Pickup Artists that I usually recognize their techniques very fast.

They are not very creative because they all read the same books, blogs, and forums, in order to get ideas. So many times if a guy says something weird to me on a dating site, I can put that EXACT phrase into Google and find the forum he got it from. And they don't just share the same opening lines and negs. Sometimes they use whole STORIES from these sites.

Anyway this incident happened to my guy friend recently. And for some reason it sounded like the sort of weirdo thing a Pickup Artist would do. But I have never heard of it before as a technique but I was wondering if someone else had.

My friend was playing pool with an attractive girl he met recently. They decided to play against two random guys who happened to be there.

The girl was attractive and my friend is also on the more attractive side for a guy (and he's extremely likable with really good social skills). 

At some point, he realized that one of the guys they were playing against was drinking his beer. There was no mix-up - that guy didn't have a beer of his own at all.

My friend said "Hey just so you know, that's my beer man."

The guy looked at him, picked the beer up again, and drank more of it.

My friend did not know what to make of this, and just decided to ignore it.

What do you think? Weird PUA attempted dominance move? Or just an odd person?

Can you give me the gist of the text in a nutshell?
<bot>: Is it a Pickup-Artist technique for a guy (23/M) to drink another guy's beer (23/M) deliberately?