This just doesn't seem feasible in the real world. Sending out high frequency sound from a device is one thing, but having the other devices actively listening for the sound, is quite a feat. It's mentioned inside a block of text in a quoteblock in the article: "The inaudible code is recognized and received on the other smart device by the software development kit installed on it.". From where does one get this SDK installed on their device with enough permissions to actively listen for its counterpart ad? There's just too many points of failure for this to be a real threat, or a real marketing tool for that matter.