We got a nice surprise when we came home from our road trip in the US, our car rental company Dollar (same as Thrifty!) billed us for using the ezpass while we chose not to use this when renting the car.
Total cost was 258,94 dollars
They said we turned on the transponder, and gave us alist of toll's we had passed... thing is that we never turned anything on that had to do with this, or even new how... after calling them they said we were lucky because if they calculated alll the fines it would have been around 800 dollars.
After that i actually checked the locations, and it turned out that ther wre a lot of locations we had never been, and the others we on dates that we were in a completely different state. all movements were in the new jersey, new york and delaware area, while we were in virginia and middle pensylvania.
My point is be aware when renting cars from these companies, and ask and keep receipts of every toll passing!