There are two interesting issues there:
- Most of people don't read license agreements, release notes, advanced settings etc. We can safely assume that most of people will just install this new version with the "share search results" option set (or what it's name was).
- Although Google would not abuse or share those results willingly (or would it?), we can envision the RIAA getting a court order to find all those mp3's and avi's sorted by user name.