Your first paragraph stating your supposed superiority turned me off immediately. Stating you are Platinum with enough travel to "know what to expect from a Westin Hotel" was unnecessary. Your status shouldn't give you recovery privilege more than anyone else. Notes that start out like that do nothing but give the hotel staff a chance for a good laugh and a roll of the eyes.

If you are such a seasoned traveler, why did you not inquire at the Bell Station/Front Desk (I know they are two different spots at that Westin) regarding your early checkout to see that your vehicle would be ready for you? I find that a very common practice. That does give the hotel a chance to be sure that your car is pulled - since you failed to ask for a receipt for the car (if it isn't offered, surely you normally ask for one, right?), you were "assuming" things not true in practice at this hotel for early departures. Perhaps you should make this part of your travel procedure in the future. Even with your Platinum status, you may not know everything for every hotel...