Academic Justin Papka published a detailed study of the Mugabe Hong Kong incident in the journal of the Brussels School of International Studies. He argued that the inviolable immunity extended by governments to heads of state also extends to their spouses.
"For this reason, rather uncouth circumstances such as Mrs Mugabe's are typically tolerated by nations in the interests of sustaining positive and efficient relations," he argued.
"The application of head of state immunities to family members is a practice that is bolstered by international customary law, rationality, and the desire for effective mutual relations between sovereign states on a diplomatic level and within a strategic context ..."
This leaves Mugabe's alleged victim Gabriella Engels, a citizen who is promised protection by the South African state, high and dry and betrayed.
In reality, while she is first lady, Grace Mugabe can do whatever she likes here. She could even walk into this newsroom and punch the editor of The Times on the nose.