Blacklist the greenlist. I cannot repeat this enough. Do not accept money from them, or send money to them. Do not process their transactions if you mine directly.
How about more meta than that: Whitelisting schemes require you to constantly use whitelisted addresses. Blacklisting schemes are more powerful when the blacklisted parties use constant addresses.
So there is a behavioral difference in transactions which are compatible with a white/black listing broken fungiblity universe: They constantly reuse addresses. Reuse is already a long term known-bad for privacy thing so why not depriortize transactions which reuse addresses?
You want the fastest confirmations? Transact in a way which is not compatible with white/black listing.
And its already a reality:
Eligius (15% network hashpower) is now experimentally limiting reuse to once per block.