Ask your friend for a backup of it or something, because if this were to be implemented there would be a new type of person like instead of griefers they would be thievers or something. They could go to any server with a super awesome building and copy it then say its theirs.
A day ago, i build a path thing around a giant level of my friends. It was awesome. Next day when he hosted. It wasnt there.
Is there a way to save Online Levels? Or should there be?