Many businesses have promotions with limitations such as expiry when the value is unused for a period of time. Prepaid phone and gift cards are prime examples. They are still bought even though there is no discount offered for prepayment.
Assets and liabilities are in a ' balance sheet' that should include any deposit made for a reservation or promise made for service to be provided. Should the seller omit or misrepresent a value or liability the buyer has no responsibility to honor it. The customers issue is with the previous operator if the new operator demonstrates de facto they had no knowledge of the liability.
My congratulations to this park, one weve visited, for addressing promises made while they sort out the issue.
There is always a clause determining a time limit on redemption of that promise, or refund of deposit within limits. All of you understand and accept these practices, likely even encourage them.