Annual Pass and Parking

What’s up with the first day rule? Does that mean that if I go to the park with a valid Annual Pass the first day I go the parking isn’t free? I don’t quite understand that rule. Is it because the Annual Pass isn’t active until I use it for the first time?

That was my understanding of the rule as well. I expected to have to pay the first time I used parking with my preferred pass. I did not. Your mileage may vary.