Just checked in my wife and kids for a flight - which was originally booked into Classic economy and the upgraded to business via the comfort package.
To my surprise, at web checkin, a window pops up: "your economy light tariff doesn't include any checked baggage - but you can purchase baggage allowance".

I called the hotline and the lady said "Oh yes, web checkin still shows this". And then she verified in the booking that there is indeed the allowance for the classic fee.

Why do they make their tariff structure more complicated than their IT can handle ?