What was the one "large scale prank" they mention that prompted this? I've seen a few HN posts with inappropriate map edits both funny and not, but I didn't think any of them qualified as "large scale".
This reeks of bad product management. Surely a good pm and eng team could come up with a more sensible solution than shutting all edits down. This is clearly a second rate product inside Google. Probably managed out of a remote office w bad oversight.