My guess is that the Disney legal team set it off.
Ok, I'll be more specific. I should have defined my thought better, something set Disney decision makers off on this idea, legal, Resort management, whoever it the decision maker was.
It didn't just strike them out of the blue that they needed to come up a policy everyone would hate, guests and front line employees the like. It wasn't on the list of goals to come up with something that is going to annoy their guests more than any other policy in the history of WDW (even including FP+ or making a cake out of the castle).
So after reading all of the first hand guest experiences and the many comments about this policy I come to the following conclusions: Disney legal started this to prevent lawsuits from a bad event; Disney isn't giving information to the guests about this policy and when asked they get defensive; there is no one policy followed by cast members- some are accommodating, many are outright rude and bullyish; they are treating napping, sleeping, bathing, sick guests as criminals and they will not give them peace and quiet because they see them as potential threats who are holed up in their room doing no-good; in the end the bad event they are trying to prevent can certainly happen as this policy does nothing but annoy paying guests. One who wants to engage in unlawful behavior can certainly still do so. And if something happens, lawsuits will follow and this policy will be labeled ineffective.
More or less. I think they get defensive because they probably haven't been told why either. Or at least not all of them have. They can't defend it because they don't understand either so they get defensive.
And this is not the first time where a little power goes to the head of some with the power. We see that all the time too, at Disney and elsewhere. Some security guards at gates run their gate like a prison, quizzing intensely while others wave everyone through without a glance. Similar problems with bag checks, detailed emptying of bags to barely a look inside.
Without a clear policy in place for this procedure these power hungry types are prime to abuse their small bit of power.
This is what needs to be fixed first and foremost. Give these poor folks procedures (set procedures) to follow.
I'm not sure how much the guest should be informed of the policy. It's never been a secret that a hotel owner can enter your room at will. That is not a change here. They way they are doing it is though. I think with the right procedures in place it will help.
The one guest that should be told something are those who decline housekeeping, at Disney's request especially. They need to be informed that declining housekeeping will prompt your room to go through a daily security check instead. So it's clear you do one or the other.