I believe that the Secret Service visited Where's George not because their activities made it impossible to reissue the notes (it didn't), but rather, the problem was that applying commercial advertising to money is illegal. And the "Where's George .com" stamps amounted to commercial advertising in the eyes of the government. I think the court would tend to uphold the most recently-enacted statute, which would be the HPA.
Daniel Carr is doing some really creative stuff. I think this "gap filling" is the best that has been done for years. There can never be any fraud on these restrikes because no one would ever try to spend these at face value.