And that second type of thing is what I'm talking about. It's usually not huge corporations hiring people off the books, but smaller shops or people working on their own. And it's easy for a country like denmark to keep everyone on the books, because they don't have 12-15 million illegal immigrants in their country. (Not to mention that it's a bit disingenuous to imply that the reason illegal immigration isn't a problem in Denmark is because of their rigorous enforcement).That is lack of accountability. If the companies allow such "off the books" and do not get busted and fined for it, then they will continue to do so. Its the same principle as your illegal immigration problem. In Denmark we also have the problem like everyone else, however it is at the real low level.. pizza bars and stuff, since the consequences of getting caught can be very high. People have actually gone to jail for hiring off the books. The main problem of the "dark economy" is friends giving friends help.. a plummer doing work for a carpenter and visa versa. That is much harder to deal with.