Is there a way to disable Genius updates in iTunes?
According to this Apple iTunes page:


  To turn off Genius, select Turn Off Genius from the Store menu. Once
  you turn off Genius, iTunes will no longer send information about your
  iTunes library to Apple.


This About.com page also notes:


  If you want to completely turn off the Genius features, not just hide
  them, simply go to the Store menu in iTunes and choose "Turn off
  Genius."


I've confirmed that it can be turned off in the iTunes instance on my MBP.