Aren’t “OK Google, hey Siri, hey Alexa” all processed/recognized locally? Otherwise, it would be a horrible idea to send EVERYTHING off to the internet for processing. Not even concerning privacy issues, it would just be unworkable that way.

(This is at least true for the iPhone, Hey Siri is recognized locally before anything is sent off to the net)

Re reading your comment, I guess you mean: the sound processing goes through the local microphone no matter what, even if the audio is only forwarded on if they lead with certain keywords, right? In other words, just like how every other voice activated system has to work. The privacy implications are that the equipment could be compromised to actually put the recording in longer term storage, like a bug or something.