As far as underground business goes in the US, think about it. Not all of the millions of people not on pay-rolls are on welfare or homeless. A lot of people manage to spend their whole lives without being employed or leeching off taxpayers. They sell goods and services without feeling the need to ask the government for permission to exist. I can think of plenty of people I knew doing this when I was a kid, though i didn't really think about it at the time. It wasn't like I grew up with a natural interest in whether people jumped through government hoops or not- just whether they offered something of value.