Your reasoning is unsound, and you've proved nothing aside from the fact that you either a.) don't know the definition of requirement, or b.) don't care to use it. In any case, let me help you out a bit.

requirement n.

Something indispensable: condition, essential, must, necessity, need, precondition, prerequisite, requisite, sine qua non. See necessary/unnecessary.

P.S. No Valet has ever driven my car, but it is possible that someday I may be required to use a Valet service. Should that day come, the tip will be based on the extras, like not moving my seat/steering wheel/etc, not for the act itself.