I'm confused? Since when do banks perform a currency verification service?? Of what value is it to the bank to do this and what liability does it present? I would hope you have an automated way to do this and it is not some teller sitting there doing it by taste and feel
I would not be performing such an action and would recommend that the customer contact the secret service if they want their currency verified or buy a counterfeit pen. If you run across something that you think is counterfeit, the individual realizes that the bank will seize it and not return it to the individual - right. They could also start indicating that the teller and bank stole some of the money during the "verification" process.
I can see a huge scene in the lobby over something like this as the individual already probably is playing with a short deck.