Hi, is there an obvious reason for the bars on these, and other airline sizers ? Wouldn't it save a lot of trouble if they were boxes, if the case fits hey presto. I have read of some budget airlines that insist it doesn't fit the gauge, even when the case has been measured to fit the requirements. So how exacting are the bars ? A box surely would be the answer wouldn't it ? Myself, I am going to take my case to test the gauge before travel. I don't want any surprises !