Haha I do taxes for a living, and the number of times people have said, "My buddy does this and he says it's fine." As if the fact that the person hasn't been caught is evidence that what they're doing is legal. It's what you mentioned, they feel clever and don't think they're doing anything illegal.
See a bunch of people in this thread finding out they're probably committing tax fraud by underpaying themselves from their own s-corp to dodge taxes.