That, IMO, is the only way you'll ever get widespread adoption of DRM techniques.
The track record isn't that good. What has been effective so far?
DVD Region coding? Nope.
DVD Content scrambling? Nope.
Copy protected audio CDs? Nope.
Product activation? Nope.
Something that have got people to buy games like Counter Strike is that they need a good serial number to play on the official servers.
But that is about "Free as in Beer". Not "Free as in Speech" as Jamie was initally talking about.