How would that work? I guess they could tax you on your last return. Did you move out of the state? Did you make over 300,000K (or some other arbitrary number that will go down over time)? Then you must pay a 90% penalty for not keeping that job in the state. But then I wonder what happens when someone leaves the state because they lost their job? Also wouldn't that violate interstate commerce? I guess they could do it like Alaska, but in reverse. You know the default tax rate is 90% but if you currently live in CA it's reduced. I guess everyone would move on 1 Jan ;-) I just think either the law would end up being illegal or completely inneffective.
It’s called by a couple of names: “Departure Tax” and “Exit Tax”. Both can be Googled. I think it was hot and heavy a while ago, but hanging in limbo right now. If high producers continue to leave the state, though, I expect they’ll dust it off and try again.
You’re right; it is illegal. Isn’t “mobility” to move among states one of our rights? Not that anyone in D.C. or California has a clue as to what’s in our Constitution or other documents.