Well yeah because if they are not at fault, then insurance doesn’t have to pay out. No eyes need batting.
My point above was that it’s a big risk to take with insurance in order to save the cost of sales tax. Maybe you could get away with it. But you might not. Or even if you could, it will cause a lot of headaches for you. Insurance companies will do everything the can to avoid paying out a claim. Something like registering a car in Montana, when you live in California and the car has never been to Montana is the kind of thing an insurance company would jump all over and use as a tool to deny paying a claim.
Personally, that risk is not worth taking to save paying sales tax. But as always everyone’s mileage may vary on their risk/reward meter.