As far as being notified about impending doom, I figure there will be enough signs of something going wrong to figure it out.
The Empeg is one reason I didn't know about 9/11 until long after I'd gotten to work that day and settled into my workday. I actually had to get a phone call from my wife to learn about it, since my job didn't require me to interact with anyone at the office for a lot of my day. Things did seem unusually quiet at work that day, as if lots of people hadn't come into work that day, but I was just enjoying the silence when I got the phone call.
On the other hand, it probably would have been the same even if I'd had a CD player, I probably would have been listening to CDs that morning.
But it's an interesting point... we're a culture that expects to get our news and alerts from the radio. With the popularity of MP3 players, where do we get our alerts? I like the SMS idea.