I think that searching for the "<gamename> players" group and quitting it would work (didn't check it though, if you try it you can confirm if it works or not for other players who might be interested) I strongly hope this works (or at least there's a way to remove unwanted games), but it...
For fast turn based games only(8moves /day and above),there's playtime(12hour).For example :from 2am to 2pm. So from 2pm to 2am,the clock is frozen(doesn't decrease).
For turnbased tables, plz upvote this:
"Restrict low karma players from joining too many TURNBASED tables/ tournaments" https://boardgamearena.com/bug?id=52353