When it became known that Michigan State Police had been using the tool to access cell phones during traffic stops, it raised concern with the ACLU... You'd be surprised to see just how much data today's smartphones can store -- and police can access...
What's up for grabs?
"...all of our contacts, call logs, voicemails, text messages (deleted ones too), all our notes, recent map searches, Facebook contacts, all locations (WiFi and Cellular), and current and deleted photos." (more)
Tip: You can give up your phone voluntarily, or hold out for a search warrant.