I agree. Anyone taking space that's already used, for their own private residence, should let the rest of us know. It's only decent.
Then you must know how it feels to have people do shit stuff that affects you and not get any say. It sucks. It's not what I want for people on this island.
Once someone lives there, it becomes their home. Not everyone would be comfortable asking them to leave it, even if it's only for a few hours. And they'd wonder if person living there was going to make changes to the opera house that would affect their shows. An simple net post beforehand where they can work it out, solves all of that.