"approved cabin luggage" tags were slapped on our carry-ons by NWA in HKG recently to circumvent the super-strict carry on policy instituted by the airport authority.
I still don't understand why an airport cares if a carry on is slightly bigger than the metal shell they make you put it in before you get into the airside of the airport, especially at an airport where virtually every plane is a large, wide-body plane (with plenty of overhead storage space!!!)