Oh, it would break the universe 🙂 Your thought was on point at the time - warning users about the consequences of deleting something that should not be touched. The Nexu plugin did a similar thing before Umbraco implemented it itself. But, even with Umbraco doing that for us now, we've still experienced people deleting stuff and totally ignoring warnings. The only solution to the "problem between chair and keyboard" was to prevent deletions for anyone - even admins.