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? How many cell-phones are still going to be running on day two of whatever disaster either because people have turned them off because they "don't work" because the local cell is down or because the batteries are flat? How many of those that aren't would be captured by an initial text message anyway? How many people are going to crowd around the only working phone in the area and turn on the radio to tune in and then hear something that might save their lives?
And what are you going to tell people that they don't know already (but should) and which will directly contribute to saving their lives better than, say, common sense?
Maybe it's just because I live in a country where emergencies don't really happen on this scale (no seismic activity, little flooding, no drought, no tornados or extremes of weather, no civil unrest, etc.) , but I'm one of those people who reads up on anything risky before I do it, and I'm still struggling to fathom what could be sent that would make that much difference?
Shelter locations, possibly? Surely the best is word-of-mouth and going and finding those people in need of shouting at with a big shouty-device? Like the first thing we do in any such disaster, send the police round and the helicopters over to give out such information? And anyone in a dangerous area, in need of shelter, will move away from the danger and can then be corralled and treated once they are in a safe area, any safe area? And, again, a simple text message serves the same purpose and probably uses the same power given the "always on" nature of cell connections on modern phones.
What's a real scenario where one-way FM radio on a cell-phone would be a real life-line for anyone but the completely ignorant and inexperienced?