Thx

In doing some more research it may be that the hertz car has an electronic toll 'beeper' that is electronically processed immediately and not on a 3 day 'lag'. So there is no look up of the hertz plate.

IMO set up the account in advance from a normal computer- put in any made up registration to get past the account creation process. Get your CC details in, etc.

Then, once hertz gives you the car, log onto the account. "add a car" at the airport/hertz office/coffee shop/etc. The add a car process is a lot easier on a phone, i[ad or borrowing a computer somewhere.

I am very surprised that it is not explicitly stated in the Hertz T&Cs, but is described on a descriptive webpage.