They don't stream to your phone when taking a video or picture. The data is on device and transferred later. It also uses wifi direct not BLE. It seems many many people on HN have absolutely no clue how the meta glasses work lol, there's barely any accurate information in this thread.
Like I mentioned in the text, I haven't looked into Wi-Fi yet. The picture/video -> transfer through the app is correct, and why an alternative method for detecting actual recording is necessary, but I'd expect to see that most events like battery status updates would be over directed BLE, since the initial boot + battery status is broadcast. And likely BTC for streaming audio. I'm unfamiliar with Wi-Fi Direct specifically, are you familiar with the process of scanning for active Wi-Fi Direct services?