Well, I am not sure that Florida laws for "public lodging establishments" would also apply to private timeshare (or DVC) owners.
Who said any of the people involved here were DVC members?

Assuming it does, perhaps a special assessment should be enacted and held in escrow from all DVC owners from which late departure fees could be withdrawn when owners (or their renters) do not leave (or return to the room) by checkout time.
Not gonna happen.
I would say it is probably also against the law for someone to return to a room which should have been checked out of and use the room and amenities after it has been assigned to someone else. All the stories in this thread of people who had strangers walk into their rooms, or returned and used the room after it was cleaned are just horrendous. Illegal entry, trespassing, invasion of privacy are just a few laws that come to mind....
And the fault clearly lies with Disney for letting that happen. They should never let an arriving guest into a room that still contains another's belongings, nor should they allow multiple parties to hold valid keys to the same unit.
Sometime after 11am, housekeeping should get into the room. It should not be released to a new guest until housekeeping has departed. At that time the lock should be reset so that the departing guest no longer has access.
I am trying to understand why any DVC owner would be encouraging folks to retain occupancy after checkout date/time or why they would encourage anyone to feel it is ok to go back into your room after checkout date/time has passed? Finding loopholes to allow them to stay later is not the intent of the law...
Who made statements to that effect?

My position is merely that automatically locking people out of rooms is unnecessary, ill-conceived and apparently illegal. If housekeeping discovers someone in a room after 11am, management should be immediately notified so that they can deal with the situation in the proper manner. If the guest indicates a desire to pay and remain an additional night, that is within their rights. If they don't plan to stay another night, the hotel can have them removed. This isn't rocket science.