After thinking about this, I think my official policy on this will need to be:
- If someone intentionally spawned the wither near the commune with the specific intent to grief people and cause harm, I will treat it as any other griefing incident by reverting the damage and banning the person responsible.
- If a group composed of several commune residents spawned the wither near the commune thinking they'd properly prepared for it and actually hadn't, and it got loose and caused damage, I don't think I'd do a rollback. This, I think, could be treated like accidental creeper damage to structures: the responsible parties would be expected to repair what they can and help with reconstruction.
The second part of that might depend on the extent of the damage. I know a lot of people have spent a lot of time making stuff and I wouldn't want to see a barren crater there.
Why don't we just have all intentional wither spawnings do it someplace away from civilization, so that makes it easier