He clearly violated their Terms Of Service. If you like and enjoy a service, exploiting it to prove a point is not the way to do it. It takes no time to spot the clause about exploiting the service.

Legally, it wouldn't be good to have a TOS and then not enforce it. You never how that could bite you later on if you get dragged into a dispute.

All this "they should give it back when they're done" is pointless. You can't reward stupid behavior.