Earlier quoted context omitted.
Yeah. I took my partners dog for the afternoon. It has an airtag (not an official supported use). I knew the dog had it but there was some comment made about our walk. Monitoring by proxy. When I worked at a power monitoring startup (we monitored home power use, by individual circuit) this passive monitoring came up. And our CEO mentioned to his wife that she was home early.. "how did you know?" He saw the garage doo…
Someone told me that by examining smart meter data by amount, time and duration different appliances could be identified. He was rather surprised himself by the level of detail.
Or perhaps they could correlate a person's anonymous internet activity with their use of electricity.