How do you force Google Search App to keep Safe Search Filtering on My son just got a Nexus 4. I installed K9 Web Protection which does things like blocking other browsers, forces Safe Search to be on, but it also blocks Google Now by default. He really wants Google Now, but I do not want to allow Safe Search to be turned off. 

At the moment, I see no way to keep Safe Search enabled on Google Now. Does anybody know how I can do this? Thanks.

Oh, this is on Nexus 4, Android 4.2.
After quite a bit of searching and testing I don't think it's possible to do. Even locking SafeSearch on your Google account on the PC doesn't change it for the phone. 

Regardless of this I would imagine that if your son can turn SafeSearch off even if you did lock it he would probably try getting around K9. This isn't too hard, there's even a suggested method in the product reviews, it apparently doesn't stop you from browsing within another app.