...or teaching what they say are their ways to others. I suspect that the way some have been able to peddle their "pay no taxes" seminars and books for years without getting busted is that they themselves know that their methods do not work and so they actually do pay their taxes.
This does not occur to their gullible students, who take their teacher's continued lack of indictment as proof that the methods work.
People use them to "pay" their taxes; car loans; utility bills; etc.
http://www.quatloos.com/Q-Forum/viewtopic.php?t=10879
http://www.getoutofdebtfree.org/forum/viewtopic.php?f=60&t=9...
(There's a BBC programme about this, I'm trying to find it now)
http://www.bbc.co.uk/programmes/b0783lmy
See also Guy Taylor at Bodenham Manor - these people can rack up huge amounts of debt before the system catches up.
Also: Someone can become rich before they become mentally ill. (If we're assuming these billboards are a result of mental illness).