I wear one of these chips on my wristwatch since the 125 kHz RFID lets me open doors and use the elevator in my building without needing to pull out my keys. It’s entirely passive so I’m guessing that the chip in question carries an ID that is read by a reader and points to an ID on some pet identification database. So she was “updating the chip” less and “keeping the database up to date” more.
Ubiquitous microchips are really quite amazing.