EZ-Pass is RFID based, it doesn't use license plate scanning but a transponder you have to have in your car (typically it's affixed to the windshield, but it doesn't need be)
I've spoken to the Chef Technology Manager and the Chief Executive Director of E-ZPass for some research I did with their system [0] and confirmed that it is not 100% reliant solely on the transponders, and that they do use license plate readers as well.