Well yes, I'm a designer, not an engineer. I have seen exact figures for some earlier devices, but it was years ago, and even if I would have them, they're company confidential, so I couldn't really quote them. I didn't argue anywhere that it would consume the same amount of power in those two cases, perhaps you should stop reading between invisible lines.

But calculating in layman's terms, let's utilize the 7 hours figure. 7 hours is 25200 seconds, running a 1500mAh battery. So taking 5 seconds out of that takes 1500/(25200/5) = 0.3 mA from the battery of power to display the message (in the worst possible case, as if power consumption would be 0.0 without the message). You would need some more figures for charger efficiency etc., but from there somebody could calculate how much time it takes for a idle charger to consume the same amount of power than what it takes it to produce 0.3 mA power in the battery. (if it wouldn't be such an asinine thing to calculate in the first place).

Anyway, the main argument was about big companies. When there are 3 billion mobile phones in the world, you can also say that there's 3 billion chargers. (That most are unfortunately more wasteful than the Nokia chargers.) Take even a small percentage out of these people, say a hundred million people, starting to unplug their phone - and other device - chargers and thinking about idle power, and it will have a real effect.