Thats a fair point. I think you may be right this falls on the test of public interest, where minimum seat dimensions and exit/emergency safety doesn't.
I don't personally LIKE LCC and the unbundling, I tend to believe evidence that when you are driven to LCC pricing and then factor back in the unavoidable costs it can be more expensive than the cheaper bundled product from mainlines.
Maybe the limit of regulatory control here should be "final total cost must be shown before committing" so that all taxes, airport levies, state charges, and other unavoidable costs (card processing fees?) are shown in the pricing, because I am led to believe a $99 fare can wind up $150 or more once all the unavoidable extras in that price are factored in.
Basically, I concede.