Unless it is a hazard from weight it really doesn't matter. Blackberries, Cells, Gameboys with not affect the plane. On charter flights it is not an issue at all only on commercial flights.

What I do find a hazard is a 20 pound child in someones lap. If we hit turbulance that kid is gonna go flying and I hope it will not be toward me.

What is the purpose of raising shades during landings and takeoffs. I never shut mine anyways and I hate when people ask me to. I do not do it. I like the sun light.