I think excess carry-on luggage should be charged at the same rate that excess body weight is charged.

I've often wondered why a child weighing 40kg & paying full fare would be charged extra if their carry-on luggage exceeded 7kg, but a lard-arse weighing 130kg can travel for the same price as the kid. Doesn't seem fair to charge the kid extra if their carry-on is 1 or 2 kg over weight when a ...