I've seen a steadily growing increase in teamers in quick matches. I'm not talking about when someone suicide to prevent a team with the most crowns from winning, I'm talking about teaming from the very start of the round.
I don't recall there being an option/way to report teamers (the in-game report menu has no "teaming" option), so I assume it's OK.
Maybe someone can explain why this unfair advantage (basically having extra teammates) is tolerated.