Can't imagine that will be legal.
But there is a point to what he said, many people can pick up cell phone calls since they are3 being transmitted openly through the air. but I don't think that should give the gov't the right to monitor them legally.
The calls and their contents are not at issue, only the location of the phones themselves. Which is determined by the transmission of signals through unprotected, public space. I understand the argument.
But that argument ignores the nature of the cell phone as a personal object most people carry on their person, in which case it should receive the same protection as other personal items worn or carried on one's body.
I personally don't like it, we already split way too many hairs with Fourth Amendment protections. But I can see how it can be justified.