The caption may not even be right either...it's not even from the people who posted it, it's someone who took a video, put a caption on it, and reposted it; you can see her at the end.

All you see is him there writing something with a pen in his hand.

There are a ton of empty bottles around.

As long as we're adding random stories, without any facts...going off the footage, we can maybe say he was called to a party for a noise complaint; shows up, asks around who's party it is, and is writing the girl a ticket.

Why else does he have the pen? Why is he in uniform if he's there to "drink and smoke"? Why is he not drinking or smoking while being filmed?