"Since the Fair Tax is 'inclusive', it wouln't appear on a sales ticket any more than the flat tax."
Where do you get that notion? The federal sales tax would appear on every sales receipt just as the state sales tax does now.
As for testing the flat tax vs. the Fair Tax, several states have just a sales tax and can be compared with those which have just an income tax. Plus the Americans For Fair Taxes has spent over $30 million in doing research. Their results are available at www.fairtax.org.
I recently rented a room in Chattanooga, TN and got hit with three sales taxes and all three appeared on my receipt. Believe me I noted the increase from $139.00 to $162.98 and so will most consumers.