i cannot see how engines can ever be 100% banned because:
1. clever engine users can always use them selectively at strategic points to win their important "key" games (for example, to toss a major clan match in their favor, or maybe get a tournament win)
2. idiot engine users are just idiots; who could possible take any pleasure in watching their Fritz play someone they don't know?
3. malicious engine users - those who take joy in messing up the pleasure of others - use their engines and their ratings to mess up tournaments and clans. they are readily identified and booted from RHP - after their damage is done. then they reappear with a new user name to start all over again.
Rec'd: report them, ignore them, feel sorry for them, ID suspicions in public (just post something like, "hey, check out this user's profile" in a public forum, then everyone can see their 1100 rating that zoomed to 2100 that crashed to 900 that's back on the way up)
just my 2 pence