All nodes that generate blocks (transmitters) must register and (I assume) to be compliant must know both parties of all transactions included in the block. This is impossible and thus the guidelines make Bitcoin illegal [in the US and wherever FinCEN thinks it has jurisdiction :-)]

I would urge the US Bitcoin community to discuss Bitcoin with FinCEN. There are positive statements:
- bitcoin is not a currency
- Users of bitcoin do not need to register.
There is good will from the other party :-)