Over-blocking is our major concern BigJim. Technically, the UIGEA does not protect ALL over-blocking, only over-blocking that is reasonably motivated by a desire to comply with the regulations.
But since the regulations fail to define, or even help discern, what exactly is "unlawful internet gambling" the room for a bank to say "it was reasonable for us to think online poker may be unlawful" is pretty clear.
Further complicating the issue is that fact that banks are not required to accept your business. So if a bank decides it wants nothing to do with any online poker transactions, nothing stops them form making this a condition of having an account. SO a bank may choose to simply close your account once it becomes aware you do poker transactions because it does not want to spend the time to really decide if the transaction is legal or take the chance that the analysis may turn out wrong. And since it is a still-to-be-decided question, they are far more certain to get a pass by blocking wrong than by allowing wrong. That is the evil incentive in this law in a nutshell.
Still, at least the regulations do not really require that much actual monitoring of anything other than credit card transactions. So maybe most banks will rely on that aspect of the regulations and not go looking for possible "restricted" transactions in any other manner than with commercial accounts and credit cards.
We can hope.
Oh, and yes the regulations do allow for banks/financial institutions to allow transactions if they have a reasoned legal opinion from a lawyer that the specific transactions are NOT "unlawful internet gambling." This provision is directed at banks and their commercial customers, however. It is unclear if we can utilize this provision on behalf of players.
Skallagrim