Recently when traveling through Miami and Dallas on AA all the window shades, including those at the over wing exits were closed for boarding, presumably to assist in keeping the aircraft cool. There was no instruction to open the window shades before takeoff, including the over wing exit shades which I would have thought would be the minimum as the person opening these has to ensure they are safe to open. But then again there was no overwing briefing on any flight we took when seated at the overwing so I guess different authorities have different standards. Personally I would prefer worlds best/safest even if a little inconvenient/annoying