There are more than 21 million illegal aliens (and not the ridiculous 10 or 11 million the government throws around) and those folk alone represent a huge amount of tax revenue as do drug dealers and others currently not hit by the income tax.
Nothing that could be devised under the FairTax in the way of some black market goods operation - NOTHING!!! - would even come close under the FairTax. And that's ignoring the many other forms of tax evasion that go on under the income tax at present which even the IRS admits is huge.
I'm not certain that makes sense to me but I think my reply would be that I do not believe what I think you are trying to say is at all accurate.