I'm sure the OP now knows that the general consensus is to ignore the phones (perhaps absent some concerted effort to "test" the ring tone during a FT).

It seems to me that we are starting to "pile on."

Agreed Bob.

Cell phone rings are not possibly loud enough to detract from the game. This is something that should be ignored. There is no need, IMO, to make an announcement to have the phones turned off (or put on silent). A screaming person is louder than a cell phone any day.

-Josh

Rule citation that says this applies during a FT? I know of no rule that says it has to be church quiet then either.

This is basketball -- played in a gym -- not watching a movie in a movie theater. This is borderline asking all spectators to sit on their hands.

There is a rule about artificial noisemakers. Not that I would necessarily apply it here, but if a group of people were to make their phones ring during a free throw, I could see having to deal with it. Maybe.