In the Tappening case above, I don't see the exercise as seriously one of fighting lies with lies - more a facetious way of underlining the lies spread by advertising. My beef with it would be that it's preaching to the choir, not that it's despairingly showing that we have no other choice than to lie.
perhaps turning the debasement of truth that has, to this point, primarily served those with power against the interests of those very powerful may give them reason to consider the nature and value of truth
If, finding one's self operating in an environment of debased coinage and lacking the ability to apprehend and prosecute but not the ability to identify those who are passing the counterfeit, it may be that the best immediate response is to pass counterfeit back to those from whom it came. Of course in the final phase of debasement it will be only the victims so doing that will be prosecuted. In the case which afew originally cited, humor can serve both to protect the victim of the lie and to expose the liar. As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."