tl;dr, fix this automatically:

I'm imagining that when someone created a new room in a SeaGL space, using the Element GUI, Patch would immediately automatically recreate that room without encryption, on Seattle Matrix, etc. etc. and would close the old (just-created-by-the-user) room. We'd tombstone the user-created room in the same way we do for room version upgrades, so it gets the "The conversation has moved to [this room]" UI.