Last modified: 2014-02-28 23:51:51 UTC
Rather than simply quietly inserting pawns and other placeholder characters into the page text, VisualEditor should do a sanity-check pre-save and either outright reject or loudly warn about edits that will insert such characters.
I suggest piggybacking on the existing sanity check code: display the "your edit may be corrupted" warning in the save dialog and tag the edit with visualeditor-check.