alt Hacker News20%? That's a bit insane. This does happen in Europe but is heavily looked down up on and usually quickly corrected.
On the other hand I did get a chewing out from an older guy for having a conversation with friends on a train once, so some people take it perhaps a bit too serious.
It’s very much a thing on US public transit, with the added negative bonus that no one ever confronts the person doing it, because chances are they’re either crazy, armed, or both.