Currently when a user attempts to make a change which includes a blacklisted website they receive a "Spam filter notice" which tells them why their change was blocked but doesn't show the source of their attempt change.
With certain web browsers (particular I.E.), this means the entire attempted change is lost as using the content disappears when one uses the back button. Technically the content must still be somewhere in memory since refreshing results in another submission attempt but recovering it is obviously out of the realms of most users. If the edit was part of a large attempted change this is going to be rather annoying to the person who attempted to make the change, who may not have been aware of the site being black-listed and may not have been trying to do any harm.
To prevent this, I propose that when a change is blocked, the software should show the source of the attempted save as happens when the database is locked for example.