By looking at the rest of the world? Do you think taxation directly on winnings is something unheard of?
Plenty of countries here in the European Union that will tax any winning ticket you try to cash out directly at the source, not matter, and not caring at all how much you actually lost before that.
People in the whole of Africa should start realizing that you can't demand your government to do the same thing as other nations when evading tax and paying the lowest taxes in the world is a national sport.