Communications is the key to safety
In today's world the accepted means of communications is the cell phone, second would be the Internet. But what happens when there's no power to run the cell towers or the data centers for the 'Net? You think this couldn't happen nowadays. Think back to the time when Hurricane Katrina devastated Louisiana and Mississippi and you'll see the cell phones and Internet networks were down due to the loss of power. Even back-up generators began to fail due to lack of fuel, the oddball part here was there wasn't any power to run the pumps at the gas stations so no one could by any gas or fuel for their generators. So it all simply stopped working, people stranded in buildings and on buildings trying to communicate with the rest of the world. But they were unable to do so. Would you want to find yourself in similar circumstances? Bug out bag in one hand, dead cell phone in the other.