Correct me if I'm wrong, but zerocoin is essentially a formal, decentralised tumbling service, right? It runs parallel to bitcoin and people on bitcoin can choose to use it or not.
Under my scenario, if you used zerocoin, and anybody else using the service wasn't whitelisted, you would be blacklisted, since there would be a chain of coins being sent from non whitelisted addresses to yours. So it would just be up to you not to use it.
The key is at what stage the Government becomes involved. If they implemented this sort of proposal right now, they would just say "if you're using zerocoin, you'll likely be blacklisted- tough luck". If everyone starts using zerocoin, including all legitimate businesses, and then they try to regulate it- then people would have more power.
Under my scenario, if you used zerocoin, and anybody else using the service wasn't whitelisted, you would be blacklisted, since there would be a chain of coins being sent from non whitelisted addresses to yours. So it would just be up to you not to use it.
The key is at what stage the Government becomes involved. If they implemented this sort of proposal right now, they would just say "if you're using zerocoin, you'll likely be blacklisted- tough luck". If everyone starts using zerocoin, including all legitimate businesses, and then they try to regulate it- then people would have more power.