So I like looking outside, and I will leave my hand on the flap lever so I can extend/retract without having to go look for the handle. I think (hope?) most of the people I fly with get the point when I brief "if you fly, you fly. if I REALLY want something different, I will say something". If you fly with "hand-hover-as-a-hint" make them do something that requires them to move the hand. Also, definitely, hover back when they fly. Can still remember the guy getting really annoyed with me keeping my hand on the gear handle the whole 30 mile final, but it was worth it.
(I know, passive aggressive)