Dumb rule, but I still don't want cells on during flight. Still the rule should be complied with.
Just speculating but what if an electronic device interferes with navigation 1 in 100,000 times? Or if having 50 of them on at a time creates a problem?
To me it's similar to people who try and hide their bags behind their legs. The odds are we won't have to evacuate the plane, but if we do they've endangered other people.
Last point to consider on cell/laptop usage. If a plane does crash on landing or take off all those things become missiles in the cabin.