I have no issue with this.
Over the last few few trips to Orlando, I have made a one reservation per trip at a Disney owned restaurant for me and my wife, usually a week or so before the actual trip.
Since these trips have been in conjunction with in-laws, we never made it. In the past I have cancelled reservations, but have gotten lazy.
I have never double booked or booked just for parking.
These seems to be a reasonable policy, so they can better handle walk ups etc.
I will now be better in my bookings/cancellations.