Re-inventing the wheel
It is amazing how well known standard procedures and recommendations get forgotten over the years. What happened to the Clean Aircraft policy and the final responsibility of the Capt?
Who would seriously rather take off while uncertain of clean wing conditions, than risk "worrying passengers"?
I have many times checked the upper surface with Pax on board, following a brief PA to explain what was going on. In my experience Pax are a lot more clever than some crews seem to think, especially if treated with courtesy and given information.