I sell a white-label product, can I publish on my sales page how famous brands would look like using my product if I state on the page that these brands have no connection with me and the images are merely illustrative?
If not, would they sue me for millions or just ask me to remove?
This would seem to be a trademark issue. The key question is whether a reasonable person, seeing the ads, would believe that your brad was endorsed or was in fact being used byt these "famous brands" or their makers. That is a verfy fact-driven question.
A sufficiently prominent statement can, in some cases, make it clear to a reasonable reader/viewer that there is no endorsement or affiliation, and thus, no trademark infringement.
This is a question which cannot possible be settled for a specific case by a forum such as this. A Maker wanting to publish such ads would be wise to consult an experienced trademark lawyer who can review the actual advertisements proposed to see how they comport with trademark law, and what suits might be field and what chance of success they might have.
Fair use exception is for educational, research, academic purposes e.g. and not for commercial purposes.
