The original poster’s idea may appear good in an abstract sense, but real life happens.
I have been criticized in the past for the fact that my cell phone is always in my purse and turned on during Mass, although after an embarrassing incident several years ago, the ringer is always turned off when I am at Mass, work, or anywhere else a ringing phone would be a rude interruption. I have been told rather rudely that I should leave the phone in the car, because I’m not important enough to need 24/7 access (which is true, but that’s off topic).
At Mass this morning, one of my fellow choir members had a heart attack, just after the Our Father. I was the only one in the choir with a cell phone that was turned on, and thus my phone was used to dial 911. The EMTs arrived within minutes and started hooking the man up to life support. They were able to stabilize him and wheel him out on a stretcher by the time Mass was ended. If I didn’t have the phone, we would have wasted precious time either getting a phone from someone in the congregation or leaving the church altogether and unlocking the parish office to use that phone. If cell reception was blocked to the church during Mass, calling 911 immediately would have been impossible.
Please pray for this man. He was already not in good health. Pray that the Lord will take care of him.