I flew with SAA though so I can't speak for BA.[a href=\"index.php?act=findpost&pid=167948\"][{POST_SNAPBACK}][/a]
Why do people keep talking about specific airlines allowing whatever, when it is the airports that say whether or not you can take baggage through. Check in desks rarely even look at one's cabin luggage, let alone weigh it/check sizes. I doubt I've ever travelled under the onboard weight allowance [if there is one].
However the security guys when you go through passport control will certainly check to see if your luggage does fit in the size check frame, which of late are determined by the Government, not the airlines]. They are then are difficult if it's even just the straps that stop it fitting. That's in the UK BTW, flying back to the UK no-one seems that bothered. Obeying petty + irrelevent rules is a very British trait.
People who are like that are called 'Jobsworths'. As in "More than my job's worth."