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I think passing a law is the easy part, but enforcing it is a whole different story. IMO, the biggest issue in poorer countries is the lack of proper implementation. Sure, they can pass this law, but there’s no guarantee it’ll actually work. Gamblers will always find loopholes or ways to avoid complying while making sure they don’t get caught for tax evasion.
It's actually pretty simple for gambling locations, physical ones.
No matter how undeveloped the country is all those have to have electronic cashiers for the payouts, the government will simply tax 10% on the winnings, which are pretty easily detailed in accounting.
Some countries in Europe have done the same decades ago, and if Romania can do that of all the EU, I don't see why anyone couldn't, the bar for this achievement is pretty low already.