While filling up my tires, I thought to myself, "Wouldn't it be funny if you could track people with their TPMS noise? It's probably not obfuscated or rotated in any way like Bluetooth or MAC addresses, and everything with tires after 2008 has four to 12 of these things constantly broadcasting some sort of ID in addition to it's environmental data."

Once again, some had to have written a Flipper zero app for this, right?

Alternative use: automatic gate opener or a presence sensor for a vehicle or trailer.