Interesting. When I drove my own, Massachusetts-registered, car on the 407, going in I expected I'd be paying a toll taker, then saw the apparatus at the same time as I was beginning to contemplate the beautiful highway. (All in, so to speak.) Curse word. But I never received a bill. I guess, with a rental car, they know they have you ...and they do. Regardless of which side of the border you rented it.