There are at the moment some reasonably well-priced business class flights on MH domestic routes e.g. JHB-KUL-PEN for £187 one way, and I had been thinking to do several of these to rack up some tier points to help maintain my, now precarious, GGL status. Luckily, I discovered before booking, that such fares books into Z class, and accordingly get zero BA tier points and avios.

Is this an just oversight on BA's part, or are there business class fares with other airlines out there that similarly earn absolutely nothing?