"How many people who wouldn't think of ripping off a local charity or business don't hesitate to cheat on their taxes?"
Congress is so criminally incompetent that it lets staffers and lobbyists write bills and doesn't bother to read the results. No one, not even IRS agents or clairvoyants, can agree on what the tax code says. It's no longer possible to cheat on your taxes because it's no more possible to obey the tax code than it is to obey a telephone directory in Cantonese. Whatever its other constitutional problems, the tax code has become invalid by reason of unintelligibility.