I consider this scenario with the OP to be like this:
I went to buy something at a store, and it wasn't available, and they gave me a raincheck for another time. Great, right? But what if I went back and found the product available and then they said that the raincheck was not going to be able to be applied toward the product I wanted to buy, (because the price had now gone up.) If they told me that I could still buy it, but at the new higher price, I would feel upset.
This is essentially a hotel booking is for. You book at a price and you read about any extra fees, charges, and taxes you may have to pay. You budget and plan accordingly. When a hotel creates a change in policy, (parking fees) you can't 'go back' after the deal is written up, and tell the client they need to pay more. Was a credit card dispute taken up with the credit card company on your behalf, OP? I can't think of any credit card company who would stand for that type of thing. Any hotel should be responsible enough that if they implement a change, that those who booked prior to the change will not have to pay the fee. Their records should state what date the booking was created, and then they would know if they had to charge the guest for parking. $9 a day on every single booking - rakes in the cash - but their poor methods of early check in = pay for 2 days of parking is more than a little ridiculous. They may think they are raking in the cash but I know because of how management handled it, we too, would never stay there. I know lots of people enjoy the Tropicana, and those who have stayed and liked it very likely will remain; but this is certainly an eye opener to any potential new guests, and any profit they make on the parking will likely be lower now due to fewer guests wanting to give them a try.
Management, and how they problem solve, speaks volumes to me. This incident was speaking volumes to me too, but just not on a positive note!