Originally Posted by LonghornDXB

It would be a safety issue then if calculations for fuel etc were made assuming passengers carrying 7kg, and every passenger carried 11kg instead..

A BA 380 can somehow carry passengers with cabin bags weighing up to 23kg (though in practice most would have something between 5 and 15kg)

Its just that a number of airlines including Emirates prefers to restrict to 7kg, and base their calculations on that, and of course it becomes an extra income source.

I once paid 800 Dhs (more than 200$) for my carry on bag weighing around 10 kg instead of 7kg at DXB. The ticket itself was 1500 dhs, so more than half of the cost of the ticket was paid due to 3 extra kg.

Regrettably, the bag carried stuff that I could not/did not want to throw, else I could have just thrown stuff away.