That's fine, if it's not recording to send later when defoiled.

Better off not taking it or putting it in another room, next to a radio tuned to static.

Mind you, when I'm pocket dialled I can rarely hear any conversations clearly. Doesn't take much to muffle audio input.

Unless the phone isn't simply recording, but is harvesting the mac address (or other identifier) of nearby phones in order to expose who the reporter is meeting with. Then the microphone is irrelevant.