I have an idea, dunno if it's good. You see, noob bashing isn't the really problem. Playing mostly against easier opponents and avoiding some good players occasionally is the real problem. So problem here is avoiding and there's an easy idea I can propose: The anti-avoid rule.
It's simple. Let's say you asked a guy for TUS. He came up with a lame excuse like "Oh hombre, I gotta feed my goats." You say "Alright I'll leave snooper on, pm me when you're ready for some TUS." If he plays with someone else while you're still on channel, open a complaint topic in forum with proofs provided. Punishment could be voiding games he won by avoiding you or being have to arrange for a league game with complaint owner.
Best idea I can think of. I think similar action was taken when Prince_Egypt avoided Casso on HAL.