Never seen it happen...
I wish they would though and actually enforce the 1 bag plus laptop type thing bag limit...
So many times I've seen people who can't actually manage to lift their hand luggage into the overhead storage and when they eventually get it in (with help from CC?), they move my stuff to try and get it to fit!!!...makes my P!"£S boil really does.....

Can CC ask poeple to put oversized cabin luggage in the hold? and issue a 'on the spot fine'?