Originally Posted by
pptp
It's NOT an FAA requirement so it's up to the individual airline. CO mainline has a policy of NOT asking PAX to lower shades, ever. As far as anyone else, I don't kow.
At IAH this summer CO mainline did ask passengers to lower window shades when parking at the gate to help keep the plane cooler. But other than that they rarely make such a request, and I've never heard it on CO in regards to takeoff and landing.