||Rabbi Abadi banned cell phones during learning time long ago, since almost before cell phones existed.
People sitting around getting beeped and called during learning certainly won't learn much. He always scheduled the Sedorim in his Kollel to begin early and end early, so that if someone has a wedding &/or Bar Mitzvah he can go after Seder.
Suddenly the "Gedolim" found a need to ban phones. Now that there are cameras and emailed pictures right from the phone. What are we afraid of? Pictures? What are we hiding?