I routinely turn off my cell phone upon entering the building of the beis hamedrash. It is unfair, rude, and a public disturbance to have a phone ringing when others are davening or learning. On occasion, someone forgets to shut the ringer, and it does disturb the minyan. The only remedy is to recognize that Hashem allows distractions by tefilo, since the Satan wants to interfere with out speaking to HKB”H directly. It is there for me to intensify my focus, not to give mussar to yenem. If I was someone whose mussar might be accepted, I might have another mission.
I choose to focus on myself, not anyone else.