Shared Estate settings never allowed players to bypass the demolition provisions. The owner is and always has been the only one that can reset the demo timer on entry.

It exists to allow owners to share their house with another player(s). It could be someone helping a friend that hasn't been able to get a house of their own or doesn't play often enough to avoid having one demo, a married couple that want to share a house in game, or other reasons. The owner can control which features of house ownership the other player(s) have access to (stable and garden but not furnishing placement/removal as an example).

It was never about "blocking" other players. That's a new feature added with the Blacklist revamp this expansion and separate from the Shared Estate settings.