But in REALITY, the entrance is limited to GCH Hotel Guests, and those who visit the Hotel for a meal reservation (ad some other minor examples).
No...it is not reality that the GCH to DCA entrance is for GCH guest only. Here is why I am arguing against that point....There have been several posts of people ticked off where they think they can no longer go into the Grand for Whitewater Snacks, Hearthstone Lounge, or to just enjoy the decorations in the lobby and in reality NOTHING has changed except that now only GCH guests and reservations can enter through the FRONT door of the Grand. You are correct that you can no longer use the GCH lobby as a shortcut from the street, but otherwise there are no new restriction in or out of GCH via DTD or DCA that would prevent lookie loos from visiting or stopping by for a drink.
Anyone can exit from DCA to GCH lobby then head to DTD and all non GCH guests can still come and go freely from DTD to the GCH lobby
Your statements (or at least its wording) is implying that the only people that are allowed to pass through the GCH to DTD breezeway are GCH guests which is not correct (at least as of now)
So to clarify, what we know:
-GCH Front Door Entrance from Valet/Street: Restricted to GCH Guests and Reservation Holders only. No more walking through Grand for non GCH guests through the front door.
-GCH to DTD Entrance/Exit: No changes except addition of two metal detectors. Anyone can still come or go freely at any time, guests or not.
-GCH to DCA Entrance: GCH room keys still required before 11am (changed from all "resort guests"). PPH, DLH and other non GCH guests must use main gates before 11am to enter DCA. After 11am they are letting all through as usual. Policy is that it is only for GCH guests all day, practice is that they stop enforcing that at 11am. (but you can not still come in through the front door of the GCH)
-DCA to GCH Exit: open to all, guests or not.
So if you are in the Parks or DTD, nothing has changed in regard to Grand access.
There are some other minor exclusions. Disney has said this may still all change and be modified but above is current operating procedure so far as I understand it.