excess baggage - shouldn't passenger weight be taken into account ?

with the spiralling cost of fuel, airlines all over the world have revised and streamlined their policy of charging for excess baggage. these days, they adhere very closely to the ruling regarding overweight baggage. in the past, they could overlook a bit of excess here and there but now, they can no longer afford to do so.

excess baggage is charged by the kilogram but the charges vary from airline to airline and also country to country. if you travel economy class on sia, the allowance is 20kg. budget airlines, however, have a lower allowance for baggage.

tiger airways, for example, has a standard baggage allowance of 15kg. however, you may upsize your baggage allowance: additional 5kg, $25; 10kg, $40 and 15kg, $50. that means, if the total weight of your baggage, excluding your hand-carry one, is 30kg, you pay $50 for upsizing.

as extra weight translates to increased consumption of fuel, should not the whole load be considered? what i am trying to say is that the weight of the passenger should also be taken into account. for example, if i weigh 60kg and my checked-in baggage is 30kg, the load added to the plane is 90kg whereas a man who weighs 90kg and comes in with a 20kg baggage, the weight added is 110kg. although my overall load is lighter, i have to pay for excess baggage whereas the other man who will put more strain and stress on the plane does not have to pay a cent.

one way to get around paying too much for excess baggage is to send luggage as cargo, also known as unaccompanied baggage. to do this, you have to go to the cargo section before your flight and give them instructions for your item/s to be sent as cargo. for example, at terminal 3, you go to basement2 south.