Not Wait Staff, which seems a bit short and curse but actually not bad or rude but that other one which I don’t actually want to give credence to. I’ve been to South Africa and never heard the expression so my - across the road neighbours who are South African and regularly go home were duly asked she was horrified and thought maybe it was a Johannesburg thing. He had heard it in what he actually said were so called young yuppie areas.
So I reckon it’s one of those, wait for it, attempt at a de-gendering word. Crikey we’re not going to be able to open our mouths soon without wondering if we’ve been upsetting someone’s ego!