In Brazil, gambling was generating so much money that the government acted quickly to tax and collect taxes from gambling companies, but there is still a large gray area, and this is not an impediment to gambling and choosing your favorite gambling company
Government never skips to charge what doesn't generate money into the country, no matter the scale of the business, gambling alone generates so much money in a day and so the government had taking it into a tax system to generate revenue to the government. That's how it is in every country not only in Brazil.
And speaking of tax, how can the government taxes those if they are off-shore in the first place? And from what I understand, most of them operated illegally, that's why it's not really good to have this kind of setup in any country.
So yes, this is in the grey zone, unless the government goes after those legal entities that uses off shore gaming for taxes (as what other government do), but the question is on those illegal betting shops that uses off shore gaming. That will be a big problem specially a country like India which is big.