Shilled twice over by the production company.
Given the profitability of the show, the production company can afford to buy the car to maintain the ruse, build show interest, and avoid criminal charges.
It wouldn't be the first time they fake something of this nature. The Lincoln Mark III they "bought for $5k" was bought for $10k - $5k of the garage's money and $5k of the production company's money, the latter "donation" conveniently not declared on the show.
Of all the reality car shows out there, Gas Monkey - besides being one of the weakest offerings (frankly, only Hemmings My Classic Car, Chasing Classic Cars, and Wheeler Dealers are worth their salt) - seems to have the seediest reputation out there, even preceding the existence of Fast and Loud with the HRM scandal (granted, overblown). They have a tendency to overcompensate through bizarre shock value, of which this is simply another form.
Fact is, anyone else could create an eBay account as described here -
http://www.ecommercebytes.com/C/letters/blog.pl?/pl/2010/8/1280866883.html - and outbid the shills to the tune of $2 million - then fail to pay. Nobody would believe a '71-73 Mustang would bring that kind of money, and the repost of the car would embarrass them if the blogging media were to notice the story unfolding.
-Kurt
P.S.: First time I've seen a glued-in trunk floor patch. Looks ugly, but a good quick-fix for a forum member on a budget. Car looks like it had an older paint resto on it that went to the jambs, and someone put the correct labels on it. Too bad they had to screw with it, because it would look stunning in stock configuration.