Damn, is your country the same as mine?
Recently, a country very famous for its high taxes (brazil), the discussion about means of applying taxes has been increasingly frequent, even talking about 'sin tax' for games of chance, with the excuse of discouraging gambling sector. But they will continue to collect, the government doesn't care about collective health, so this is just an excuse for them to give the population to justify this high tax rate.
If a country charge 20% tax from a winner, the I think the country is a wikced country, who is gong to pay for the losses I had all this while? No, this is bad to be honest. Perhaps the country is trying to discourage people from gambling, this is why they set the standard that high so that whenever people think of gambling and also think of the money tax they are going to pay, they will say it is not worth it and the wouldn't even bother their self trying to win 80% again because this is nothing but clear ripping of citizens.
If a gambling is to be taxed in my opinion, the tax should not comes from the people, it should come from the casino that offer gambling games because people are losing millions to them, why not ask the money from them instead of making everyone to pay money. So.mow. The government/leaders of that country will be making money from license casinos and everyone that gambles, that's a great way to increase an IGR.