As the article says, there is a physical presence bar to meet to make this workable now, but I can't not think about clever ways that this could become a "worm" or spread digitally. Infected viral (actually viral!) YouTube videos? Robocalls that you hope go on speakerphone (where the fidelity of the attack signal may be questionable)? Or drive a car with big speakers around a neighborhood? How about a mobile phone botnet that just constantly speaks to digital assistants?