As to pain and discomfort, the Constitution forbids it
It actually forbids cruel and unusual punishment. Being shot by a firing squad or hung are likely painful albeit very temporarily so. The French Guillotine was invented to be a humane execution device. People these days are looking for the perfect mix of humane and sanitary.
I'm sorry, is it just me? What kind of information are you going to put out over FM to cell-phones, in an emergency, that will be life-saving?
It's not just you, but I'm guessing you've never been in a tornado/hurricane shelter without power huddled around a battery powered radio listening to storm updates. Sometimes the all-clear takes more than a couple hours than what the original predictions were. New funnel clouds crop up from nowhere, or reminders that a hurricane's eye can be very large and the storm isn't over. Flash floods, mud slides, forest fires, etc. If cell phones all has their FM chips enabled, you'd have almost one battery powered radio for every person in the shelter. Some could be turned off or their batteries could be swapped.
Doctors take a pledge not to kill people; I see no reason why we engineers shouldn't hold ourselves to the standard.
The original job of engineers was to build and use siege engines. An engineer's version of the Hippocratic Oath would involve not-not-killing people.