

They don’t do that now. The IRS contacts the bank, that’s licensed as a bank by the federal government, and tells them to close your account. Usually the first step is to freeze your assets, then they start taking things. The banks aren’t going to argue, they’re not going to give up their entire business just to protect you, or a single state. Even if it is California.
I was misunderstanding a bit myself. I was thinking you meant by yourself. As a state, California could possibly increase property taxes to maximize everyone’s salt deduction. As more of a long term solution it might even be an idea depending on California constitutional law. More likely though, they would just have to fight the illegal impoundment in the court. While it would likely take months to get done, changing tax law the the affects of that would take years.