In addition, they could have security cameras and review when your car was put into the space it was left in. That sounds pretty simple (easy to see in fast forward) if they're interested enough.

Plus, do you have to fill out a form on the outside of the key envelope when you return the car, saying what time you returned the car? If so, please let us know not just if you got with on overage but if you lied on that form (said you were returning at 4 pm when you clearly returning at 7 pm) whether you got hit with a penaltly fee or got banned from that location.

In other words, it's one thing to return late but not attempt to deceive the rental company about that, and just see if they care. It's quite another to return late but try to cheat the rental company by pretending you returned earlier.