Odd, I was talking about this with someone at work on Friday, but I flew from The Cook Islands to LAX in July 2010 and there was extra security that I had never seen before departure in Rarotonga. They asked everyone to show us their laptop/ipod/netbook etc on. My battery was totally dead, and I told security that and they just went "oh, ok nevermind" and didn't actually check it was dead, but still asked all the others to show it on.
So it's not a new thing as far as i know.