If they are worried about crowd levels, wouldn't they just constrain the number of reservations slots available each day to Key holders, rather than constrain the number of keys? I don't see why they would stop taking people's money when they have an option to take their money and then constrain their access to the park... I guess maybe they worry about guest satisfaction if they oversell passes and then no one can ever get a reservation?
I think that is the plan, but Disney's in a delicate spot -- sure, they say reservations aren't guaranteed, but if it's too difficult, they can easily be accused of deceptive advertising/practices, even with the fine print in place. Remember, accusations of deception can come forth even if something is
implied in the advertising. So a picture of a family
at Disneyland is deceptive if you're unable to reasonably procure a reservation to get there.
That's why I think core reservations to enter the parks will not sell out the way ROTR BG's sell out (within seconds).
I can make an argument that if reservations DO sell out in seconds, Disney is (unintentionally) discriminating against individuals who may not be able to click fast enough to secure a reservation. That's a potential ADA suit and not something they want knocking at their door.
Last, somewhat unrelated thought, if you're on the payment plan and reservations are really impossible to procure. Ask for a refund...and if they don't give it, just cancel your card, stop paying, and walk away. I haven't looked at the consequences of that, but that's potentially on the table as an option.