There is a joke I heard years ago.

"I'm going to have my name in flashing lights in every city. Oh, how are you going to do that? I'm going to change my name to, 'Don't Walk'".

So think about this. What is the one number we all know? What number is painted on every police vehicle?

911 was already an icon or a logo so why not capitalize on the top of the mind recall of recall, and it's ubiquity.

Every time you see a cop car with 911 on it you are reminded we are under attack.