My suggestion is simple:

Those on your ignore list cannot whisper, mail, trade, or anything at all that involves you.
If possible, they cannot see your trades on the Trade Tab, and hence cannot accept them.

One major turn off of the game is being forced to deal with those you strongly dislike due to harassment, scams, or whatever. The Ignore function is a very simple tool to deal with this.

It should also reduce Supports workload, not having to deal with the many player-to-player issues, and they can focus on the player-to-game issues.

I'm sure it will also drastically reduce the number of scammers, as without a large pool of people to continually harass, they will go away.

This should also help to reduce the amount of harassment, scamming and other negative aspects of the game. Just 'ignore' them, problem solved.

So simple... i'm sure it's been suggested before.
Scruffy