If you are one of those players on steam who advertises a team game for noobs, but pre-picks a team with mates and crushes actual new players, could you stop?

I'm not particularly good, and am being routinely killed off in games where "3v3 Noobs" or similar is advertised, only for players to pick a set team once everyone is ready, and then execute a perfect gameplan to crush me and other unknowing players who just wanted a chance to play.

What can be done?