Obstructions can reactivate after being destroyed, which leaves them dangling forever.
This is similar to rP22451.
I'm doing a quick hack for A24, but really we should:
- make the obstructions permanent instead of removing-adding on out of world (needed for D3151)
- split the Destroy message in two phases -> Will Destroy, where messages can be sent, and actual Destroy, where they can't.