Sorry to against the flow, but I don’t think it should be enforced too heavily. I think common sense should be applied depending on how full the plane is and how many / the size of the bags.
I travel with two bags, one is computer sized and holds my Tabs, charger, money etc and it weighs no more than 2kgs. The other clothes, wash kit etc. The second bag is well within regulations but often weighs 10 – 11 kgs. Many’s the times I’ve had to remove a few items, stuff them in my smaller bag to satisfy the check in person, then repack them as soon as I’m out of sight.