it's a thought.. I could put a "Do you want to submit your scores on-line" then send the High Score, Name and some way to identify the user, possibly with a hashed email address and hashed machineid.
This would allow the High Score table system to track the level of copied games, without submitting personal details.

There can't be any issue of privacy breach then, although the database would be able to see which licensed player is submitting scores... it would also only be a feature for registered users. This type of system was used in Unreal Tournament 2004 AFAIK

As long as the game can still be played without the on-line high score system being available, there should be no problems.