I have never seen anyone use those 'frames' that are supposed to measure your hand luggage.
I do find it difficult as a passenger though, to decide whether to take just a small case which I know is the right size for hand luggage but might be quite heavy, or to take a slightly larger case and check it into the hold and have virtually nothing in the cabin with me. I guess it's ok if it comes through quite quickly but if it takes a long time then one might regret having hold baggage to wait for.
Some passengers on certain routes do just take the p*ss with their hand baggage. You see them ........ hardly able to stagger up the steps/ramp with their so-called cabin baggage. It shouldn't be allowed!
