I hadn't thought about that but seems not a bad idea. Not for the whole of the lines but a estrategic light circuit that gives surviving light to the kitchen, for example, can be wired that way and be a signal of something going wrong. You don't wanna have 1000 watts of light flooding your house at 4am if that's the time of the failure, especially if you have kids or visitors! 
I'll leave that for a "panic mode" lighting released with a rapid keying of any switch. Thanx any way, to you and the rest of contributors so far.