I have an RTL SDR setup in a retail business receiving temperatures from sensors around the property. Besides the neighbors' weather stations I see a lot of TPMS coming, presumably, from the parking lot. I see the same cars regularly. I could definitely correlate them with the POS terminals and identify individual customers.

Most places where this would be legal there are probably much more effective ways to do it at the POS, even non-biometrically. Although yes you might consider usng TPMS as part of an ensemble.