PUT /directory/list/room/:roomID can have additional access control checks, but clients can't predict what those are

[reivilibre]

When reading PUT /_matrix/client/r0/directory/list/room/:roomID, I notice the spec says that 'servers may choose to add additional access control checks'...

Unfortunately this then means that the client can't predict whether the server will let it add a room to the directory before actually doing it. Knowing this information would likely be useful for displaying a 'greyed out' state on the form when appropriate (and maybe more appropriately: not showing it when not appropriate).

This seems related to element-hq/element-meta#287 where Element Web bases the 'greyed out' state of the checkbox on a separate factor to whether you're actually allowed to change it, which means that users who can do it are being misled and shown that they can't.