I don't think this is as much false advertising as it is an FA who didn't quite understand how the system works (and doesn't work). I do think CO should make the language for DTV very clear. The language at co.com and in the DTV seat-back card mentions the 200-mile guideline and that "DirecTV service is not available on flights outside the continental United States". But it's not clear that you can have DTV for most of your flight from EWR to MEX, but you can't get DTV at all from MEX to EWR.

I think the language could be clarified: "If your flight originates in the continental United States, you'll have live TV until we're about 200 miles from the U.S. border. After that time, you'll only have access to stored content. If your flight originates outside the continental United States, you won't have access to live TV during your flight, even once we're back in the continental United States, but you will be able to access the stored content."

Of course, it would be even better if there were a fix so that DTV access is dynamic...