That's what I was wondering too. There hasn't been any mention, and this is for a years old cellphone case that doesn't deal with GPS tracking, just regular tower triangulation. (The podcast Serial, season 1, covers an interesting cases where such data was used to convict someone for murder).

I don't see any specific mention of the Stingray in any of the articles I've seen on this, but from the surface it would seem to indicate police would need a warrant to use a Stingray to target an individual.

Anyone else got more info?