When he successfully sues for idiocy, et al, the taxpayers will ultimately get the bill.
Again, the only winners are the lawyers!
Just a guess mind you, but as I read it, Best Buy will be off the hook. Unless they made a citizens arrest, the cops are on the hook. A reasonable action to take in this situation would be a phone call to the Secret Service. If an agent can come to a jail, he can come to a store, because it's not like it was 3 A.M. Another reasonable action to take is to confiscate the money and book it into evidence, identify who it came from, write a report, and give it back later. I would guess, yes, this is definitely a false imprisonment lawsuit.
"You must use the bill! Or sue, I will!"