Don't know what No. 3's phone looks like. No.1's was always on her desk on the other side of the room, face-down. No. 2's was on her desk face-down too, but she sat next to her desk. It went off once but she didn't answer it, just picked it up and muted it.

I would not see a therapist who could not put their phone down during session. It is rude and it is also unethical to take someone's money for your time and attention without giving it fully.