So just a thought, if they are looking for highly optimized keywords that can be done locally what’s to stop them from adding common keywords for advertising.

In the given anecdote about babies and diapers, you would literally just need a baby keyword. It gets triggered phone tells the Mothership it heard about babies, suddenly diaper ads. It wasn’t listening to every single word, it wasn’t parsing the sentence, it was just looking for highly optimized ad keywords. You could even set a threshold for how often certain add keywords or triggered to avoid false positives on detection