Set the precedent that the All Writs Act can be used to make anyone do pretty much anything for any reason (this is a fishing expedition after all.) The Feds have been pushing its envelope for a while and have drawn some pretty stiff rebukes for the overreach. Terrierists!!!1!2 seems to have been the perfect cover to make this push stick.

(Ironically, wasn't abuse of Writs of Assistance one of the reasons behind the American Revolution?)