o2 iPhones Out of Stock - or are they?

Walking past the o2 shop in Richmond today I saw a large white easel with a professionally printed sign on a thick poster-board.

The sign, in branded font said "iPhone 3g. Sorry we are currently out of stock. Ask in store for more details or visit....."

One imagines that if they KNEW they were going to be out of stock, to the point where they had special street signs created, why didn't they just order more stock?

Is this a case of trying to create a buzz, but thinking about it a bit too hard? Or is this a case of trying to manage a situation that really did take them by surprise?

The website suggests the sales forcaster got it wrong and under-ordered. But they can manage to create special signs and turn them around!