CA and NY governments are desperately rapacious. From Doug French at mises.org:

Those who have declared residency in another state cannot spend even a minute beyond the allowed time in either high tax New York or California. And, Big Brother is watching. George Orwell could not conjure up a more diabolical tale than the Bloomberg story penned by Laura Nahmias and Eliyahu Kamisher.
“The minute you file a partial return you’re going to hear from New York state,” said Jonathan Mariner, who created TaxDay, an app that tracks users’ locations so they don’t overstay the threshold of days that would trigger residency status, which is typically 184 (for irony, slip a nine in after the one).
So for the really rich, a misplaced day in New York (or on the other coast, California) can mean millions lost to the tax authority. How serious is this? Nahmias and Kamisher write, “State officials are stepping up already-intense scrutiny to make sure former residents have actually moved. It’s a complex operation that involves cutting-edge artificial intelligence and tracking everything from travel to the location of people’s pets.”
Those who earn a million dollars a year or more have been fleeing New York (top state tax rate 10.9 percent) in droves since 2019, and the state can’t do without the income tax these high earners paid. Residency audits have been instituted. “New York’s auditors closely watch travel and apply a standard known as ‘the teddy bear test,’ looking to see where individuals keep their most cherished possessions to determine whether a home is their primary residence,” write the pair from Bloomberg.