I have to wonder if maybe the blinds down during day flights actually harks back to the days when most aircraft only had central screens down the aisle for the IFE. When flying on these aircraft, we used to ask pax to lower the blinds as it was the only way to see the screen. However, it certainly wasn't an order! More a request. Now, I will only ever lower blinds without a pax knowledge if they fall asleep before the sun comes up. A shaft of sunlight straight in your eye upon waking is not great. As soon as they are awake, they are welcome to raise the blinds if they want to. Surely, its just a matter of common sense!
JSL