This is one of the reasons we had the time limit. Who is doing this exactly? Names and games, everything is recorded.
They are fools if they are doing this to gain Elo. They will be matched with worse allies in team games. If they are doing it to lose elo: Well anyone is capable of playing badly on purpose. I'm not sure how much we can do about this, other than bring back the old time limits (possibly, make elo gain slowly ramp up over time until 10 mins or so, so that playing 10x1 min games only gives as much elo as 1x10min game- though people can still AFK for 10 mins, obv, this makes it just a touch harder).