That's the point. To use tax to prohibit legal behavior, hoping to bypass Constitutional protection. The preferred means of enacting gun control is not to outright ban firearms. The goal is to raise the cost so that only the well connected or wealthy can afford them.
Taxing the exercise of a right is theoretically more legally unprotected. Poll taxes were struck down. But FAET has not been.
Yup. And in this case, the next thing could be a county tax (though, paging Millcreek, I'm not sure what the county poklitical bent is versus the city). I certainly expect something like that for the San Francisco region. Slowly push them out. While people might easily be able to drive just outside the city limits, driving outside the county becomes more difficult for many.
A similar situation exists in CA with the upcoming ammo registration. Not that many people will drive outside the state to purchase (which would be illegal anyway), so they'll either pay the extra fees and do the background checks, or they'll give up shooting. Either one works for the state commies in office.
I've got to get to Idaho before they ban Californians there.