Board Game Arena

That's one game, Tichu, which seems to be particularly vulnerable to cheating because it's an imperfect-information partnership game. In order to say it's a site-wide problem, you would need examples of kingmaking/cheating in at least 10 games.

I was disagreeing with you, but I found an example of team play at "No Thanks".

https://boardgamearena.com/table?table=231401445

Notice how one player threw the game to another (by taking cards that were good for other players and passing cards that were good for his target). I looked at the history and these two players ALWAYS play together!

However, I just red thumbed them and so I don't have to worry about playing with them again. Their strategy is kind of silly, they'll never get past around 200 ELO doing what they're doing, because one player is always losing.

Now I know why they were playing 4p "No Thanks" when it's normally played with 5p.