It is not allowed to play as a team if it's not a team game.
People do team up in games, which is legal as long as all their conversations are in game chat.
I think the point here was that just because people join a game at the same time, doesn't mean they're going to team up.
2019-10-17 22:46:23 - MGSteve: Some games you're the dog. Some games you're the hydrant.