Because AC planes are never more than superficially clean except from the factory or cabin rebuild, regardless of what station they are coming from. Yet some other airlines using the same contractors at the same airports have excellent cleanliness. How do you think BR has clean planes flying from YYZ? It's not because their passengers don't throw up, pee on the floor or spill coffee. It's because they clean the planes. If many peer airlines flying the same routes with the same aircraft have clean planes and AC consistently has the dirtiest in the sky, there's only one logical conclusion.

When you get on an AC plane, wipe the tray table or the headrest with a wet wipe. Then wipe again with a second wipe. You will see the difference. The second wipe is what you would see the first time if AC cleaners ever touched it, but they don't.

​​​​So why do cleaners who do a great job for JAL not even empty the seat pocket for AC?