I'm all for suing the company, if it works. I don't know anything about the legal merit of this case, but I'd guess it probably won't work. And if even it does, it probably won't hit the scammers who made the original offer.
But generally, if a deal is too good to be true, it's too good to be true. We're absolute suckers for the free lunch and it creates one crazy situation after another. Personally, I'd tend go for the best sustainable deal in this situation, but there's also the let's-see-how-long-we-can-milk-this-cow approach if that floats your boat. But imaging that the unsustainable will continue forever "because advertising" is just nuts. Believing your own dummy spit just keeps the circus going.
There's a great adage in economics: If a trend is unsustainable, it won't continue forever. Corollary: It may continue for longer than you can afford to bet against it.