Yes you can. My ez pass has 3 cars registered. I take it on business trips and register my rental cars.
I always take mine along in the rental car as the rental company will charge a premium to use theirs. The Pennsylvania Turnpike is slowly planning to eliminate toll booths in favor of EZ-PASS and there are several new exits that are EZ-PASS only.
On business trips I'm expected to use my corporate credit card to charge tolls, but around here, it's hard to find a toll system that actually takes credit cards; most are cash only (and EZ-PASS).
Right but it is tracking the specific registered car, so it is not about money at all.
You cannot just move the pass from one car to another.