This thread is going way OT. It doesn't matter what the UG policies are. It's clear that some worker bee at the location screwed up and should not have comped the UG he did. But, that doesn't mean OP ought to be charged for the UG without his permission and after the fact.

The Hertz location, finding a screw-up should counsel the employee, terminate him for all I care. But, Hertz is stuck with the cost of its error.