What do you do if you suspect players colluding?

[shiren]

I was in a Dominion game earlier and I'm very suspicious of how my opponents were playing. For any dominion player out there, it was late game and one player would swindler the other's 5 cost into duchys, ultimately allowing the other player to win by a few points against me. The person throwing the game lost by 20 points or so. Is there anything I can do about this? What do my fellow gamers recommend?

[latexrhombus]

I'd suggest just not playing with them again. Unfortunately, I know what you are talking about and even more unfortunately, it is almost impossible to tell if someone is just playing poorly (especially when they end up losing by a lot, as you mentioned).

[Phelan]

You can go to the game's page and report that player for kingmaking.

[shiren]

thanks for the suggestions guys! happy playing