I don't see the problem. If I'm selling drugs out of my car and the police have the right to search it, then they have the right to search the paper notebook on the seat next to me. If there's a phone number in there then they can do what they want with it under the law: which could include working out where I live from it. To search my home they need a warrant. Which means they need probably cause. How is a cell pho…
You're correct that this is unrelated to the NSA's surveillance programs. However, it does represent a threat to US citizens' constitutional protections.