They should have installed proper financial support for this business before legalizing the trade, but indeed maybe good news for Bitcoin. But still a hassle for the shopkeeper.
But that would mean changing federal laws.
I'm not from the US so I am not familiar with this state law - federal law system. ...
Try this on. We've had and will continue to have cases where sheriffs (town or county) publicly announce that if any federal agents try to come into their area and arrest for (x, y,z) the sheriff will arrest the federal agent.
What? Really? Can they actually do that and have they ever had the balls to do it?