The United Kingdom maintained an income tax during the Napoleonic Wars and the United States during the Civil War. In a time before most people had regularized wage paying employment which created a paper trail how was it possible for the government to effectively crack down on tax cheating?
Since most of the people at that time were living at the same place for their entire life, they were easy to find. In addition, some people were hired to deal with it. Fraud probably existed, but I personnaly think that the fraud was more like corruption, or more to be found to the prospector's side. They were rich, VERY rich. See the story of "Vaux le Vicomte" castle if you want a good one ;)