Rugby Question

Does anybody know why South African rugby teams, both national and super 12, fly in the face of the rest of the world by giving their blindside flank the 7 jumper and their openside the 6 jumper?

Is this a recent thing? Listening to a world cup game involving them I heard Conor O’Shea the ex irish full-back saying that it was only a recent thing.

Any ideas?

Cheers.