Just out of curiousity, if they didn't release the code given the GPL2 license, could they be sued in private courts to release it?
But in any case as mentionned in other comments I believe the interesting code is more high level, or server side.
But you can do that after the infringement has taken place, as long as you do so within some period of time (60 days I think?) after you become aware of the infringement.
First, the consumer has the right for compensation (normally the price of the product). Second, the company will be forced to stop claiming that the product is under GPL. This then leads to either willing infringement (ie, removing the GPL notification once its been there), or continue misleading the consumer (Very large fines).
So far, I have not heard of any case like that. The closest was a case regarding contract law, which is tangent.