The point here is that whilst they are in the vulnerable start up phase, its a strategy that keeps costs down. there a ton of acmi guys in JNB at the moment- rates are very competitive. Especially when compared to keeping a spare frame sitting at the hangar, or worse flying it around half empty, with the associated costs such as crew, fuel etc etc...
Terms of peeving the customers off, if the price is right they will come back, most of the LCC's in SA have subjected pax to some pretty lengthy delays and have suffered no ill effects.
Passengers are a fickle bunch- they will swear off a carrier due to a horrible experince and next trip choose them again if the price is right.
Air travel is a commodity.