With the double-press of the Digital Crown – as Apple grandly refers to the button on its Watch – Live Rewind takes in an audio stream from the Watch microphone, processes it in a Secure Exclave on the S11 chip, and routes the data to the user's nearby iPhone, which runs a speech-to-text algorithm on the 15-second audio segment. The resulting text is saved and the audio is discarded.

The wearer's Watch emits an audible tone, even in silent mode, to alert those in the vicinity and provides a visual cue for those able to see the face of the device.

Nonetheless, bystanders alerted to the recording – to the extent they recognize the meaning of the tone – have not consented to being recorded, which is a legal requirement in 11 US states that have all-party consent laws.