ambiguity in consumer class actions v. the Lanham Act: convergence or divergence?

Slaten v. Christian Dior Perfumes, LLC, 2025 WL 1840026, No. 23-cv-00409-JSC (N.D. Cal. Jul. 3, 2025)

The concept of ambiguity is now on a path to become as entrenched in consumer protection cases as in Lanham Act cases. My thinking on this is still evolving, but right now I’m inclined to say that an “ambiguous” claim for purposes of Lanham Act claims means what an “ambiguous” claim for purposes of consumer protection litigation does, even though the assessment process is formally different. That is, a statement challenged under the Lanham Act is ambiguous if there are multiple plausible interpretations, some of which are not false. As the Ninth Circuit has clarified, a statement challenged under consumer protection law can be found plausibly deceptive if reasonable consumers could think it has a false factual meaning, even if other reasonable consumers would think it was ambiguous and required more information to interpret/had a different non-false meaning. That latter group can be expected to consult the back of the label for clarification, if present. But the first group of reasonable consumers has no reason to inquire further and therefore can be deceived; they are functionally equivalent to the deceived group in a Lanham Act false implication case.

The Lanham Act cases use the modifier “substantial” to describe the relevant subset (reasonable consumers who are deceived), but accepts much less than half as a sufficient percentage. Consumer protection cases are right now generally stricter, requiring bigger percentages where there are surveys (as there often are these days), so there may still be doctrinal divergence. I think that divergence, to the extent it exists, is likely unjustified—it is hard to see why competitors should have an easier path to remedies than the directly deceived consumers—but it is early days for both the “ambiguity” concept and the new prominence of surveys in such cases. 

I suspect that courts are thinking that “half or more” is better for class action treatment, but formally it really isn’t. That is, the common question in a consumer protection class action in the key states is “is this ad deceptive?” and the answer to that should be “yes” if it is likely to deceive a substantial number of reasonable consumers. Then, NY and California (etc.) presumptions about deception kick in to allow the class to proceed. An ad that deceives 49% of consumers—or 30%—about a material fact is actually pretty bad! [Caveat: our concept of deception should incorporate a “compared to what?” inquiry. If it’s impossible to provide the information in a non-deceptive way, but the information is also truthful and useful to some people, then we have to balance those considerations; if it’s not useful/the ambiguous meaning is just puffery, then we don’t have to worry so much.]

A related question is the role of the jury, at least in a Lanham Act case: If courts applied similar analysis in such cases, they'd ask whether a reasonable jury could find that a claim was literally false with respect to a substantial number of reasonable consumers, such that those consumers would feel no need to inquire further. That's not how Lanham Act courts tend to treat the issue; it would probably counsel against determining "ambiguity" as a matter of law. 

Anyway, this case involves a remand on claims over alleged deceptive labeling/advertising of SPF in cosmetics as lasting for 24 hours. The court initially interpreted McGinity v. Procter & Gamble Co., 69 F.4th 1093 (9th Cir. 2023), to mean that if a front label is ambiguous in that it “could mean any number of things,” some of which would not be deceptive, a court must look to the product’s back label to determine whether a reasonable consumer would be deceived. Upon review of the back label, the court dismissed plaintiff’s claims.

The court of appeals eventually remanded based on Whiteside v. Kinberly Clark Corp., 108 F.4th 771 (9th Cir. 2024). Whiteside held that “[a] front label is not ambiguous in a California false-advertising case merely because it is susceptible to more than one reasonable interpretation.” On a 12(b)(6) motion, a label “may have two possible meanings, so long as the plaintiff has plausibly alleged that a reasonable consumer would view the label as having one unambiguous (and deceptive) meaning.” That is:

a front label is not ambiguous simply because it is susceptible to two possible meanings; a front label is ambiguous when reasonable consumers would necessarily require more information before reasonably concluding that the label is making a particular representation. Only in these circumstances can the back label be considered at the dismissal stage.

Whiteside specifically rejected this court’s earlier “more than one possible meaning” standard for ambiguity. Bryan v. Del Monte Foods, Inc., 2024 WL 4866952 (9th Cir. Nov. 22, 2024), did not change matters. Bryan considered whether a front label describing a fruit cup using the phrase “fruit natural” falsely led consumers to believe all ingredients in the cups were natural. The court explained the word “naturals” was “a noun, not a descriptive adjective,” and so the label suggested “the phrase is just the name of the product.” Further, the front label context indicated “although the fruit itself is natural, the syrup may not be,” and customer surveys were insufficient because they “asked people what they thought ‘natural’ should mean on the label of a product, not what they thought it actually did mean as used on these labels.”

But here, reasonable consumers could conclude from the front label alone that defendant was advertising 24 hours of sunscreen protection.