I think that it would be better for the game to make it so you cant specificly search automatch games outside fo your own level range. I´d suggest that both the parameters Min Rating and Max rating can not go into the negatives. The only reason i can see for people doing this are wanting to beat up on weak and new players and gaming the leaderboard by never playing people in their skill range. There shouldnt be a valid reason not wanting to play equally skilled opponents.
I hope you consider this simple change.