sad to say, Scoot-r...but what you just said is I think the reason why the tobacco companies will win this case.
It would be a fraud if they had marketed the product as "light", without differing in any regard from the regular brands. Because the "lights" do differ, and contain less of certain substances, there is no fraudulant advertisement.
Which leaves the implication to health - which, like you say, is clearly there. So tobacco companies can't call their product light because it implies healthier - making it fall under the 'proximate application' rule of Cipollone v Liggett Group: "ask..whether, whatever the source of the duty, it imposes an obligation in this case because of the effect of smoking on health" and therefore be pre-emted.
point is, this is all because both the tobacco industry and the law makers called us idiots, took our money/votes and ran when the FCLAA was enacted. In return for the (imo useless) warnings on packages of cigarettes, the tobacco companies got de facto immunity from lawsuit related to advertisement . Outside of outright fraud, I think this SC will split in favor of pre-emption in cases like this.
The tobacco manufacturers duped us with the "light" implication and the legal system allowed it and sold it to us as tough legislation against big tobacco. And the smokers get kicked around again.
Everyone seems to have an agenda on this one, and as a smoker, I've got enough frustration to go around hehe.