You said — “Needless to say that a mandatory designation would soon follow.”
Well, I think it would be impossible for a “mandatory” designation to follow — because you’ve got a lot of out-of-state traffic. So, you can’t make it mandatory. The out-of-state cars won’t have the equipment and so the pumps have to be allowed to just “pump” the gas and charge a gas-tax at the “pump-rate”.
I think that they’ll always have a “gas-tax” differential to “persuade” people to get the equipment — but that they *always* have to have provision for cars who don’t have the equipment, because of many reasons...
Blago's toll roads in Chicago do this. The toll doubles if you don't have the auto pay device..
Out of state cars have nothing to do with the issue at hand. You are saying this would remain a “voluntary” tax but the fact is it would the first step leading to the mandatory second step. I won’t even take the time to enumerate how many times liberals have made proposals with opt-out (or temporary) provisions just to turn around and make the issue a mandate (or permanent).