Don’t delete DBLs entirely. Move the enter buttons to right side of the B window, next to EotM button. Anything done in DBLs would not contribute to the match.
DBLs are awesome maps to explore, and should not be removed entirely. Likewise, you could have kept the alpine maps in right side of the B window all this time – for that jumping puzzle, if nothing else.
Edit/PS: Some players may want to test their skills by soloing creatures/bosses in DBLs.