What struck me as the really scary part is that you could easily put this as a separate audio track underneath the audible audio. Like in a movie theater when they're showing the pre-film promos for the snack bar, you hear the audio for "fresh popcorn and snacks are available", but the undercurrent audio that just plays in your head is saying "I'm hungry, some popcorn would be really good right now". And it wouldn't be all that difficult, just put it on a separate track and use a lower level, so it's more subtle and subliminal. Or put messages about buying stuff under the Muzak in a department store....or messages about work over a company music system....