I recently rented a car in NYC. It was pretty new. I couldn't find a transponder on the windshield so I used my personal. I got a bill a few weeks later from Avis for the toll charges. Where do they put the transponders nowadays. I think they started scanning license plates so that might be how they're tagging the car. Best practice...check for transponder in the car and/or ask someone where it is before leaving the lot.