Depending on whether the players 'know better' it might be worth putting it on a recurring message just to raise awareness either when you logon temporarily or on the hints on the ladder screen.
I think it's a good rule though and, there are now A LOT of maps compared to when the rule existed prior to this and it worked just fine then.
I've heard some guys say remove the pts filter but, I think this would encourage 0 pts nicks attacking high pts nicks; the determination to win the ladder by any means necessary should never be underestimated lol. Perhaps the point filter could be tweaked to make using QM a little more accessible without removing the filter completely.
All this said I've never competed for the 1v1 ladder it's just my blue sky thinking..