At any time, any place. For example, if a blue shirt approaches me in the parking lot, at a train station, a bus station, a sports stadium and starts asking questions or threatening me, I have no way of knowing if that individual is, in fact, a TSO on legitimate business, a rogue TSO or an impostor.

We are already told we can be stopped and our bags searched at any time in the sterile area. It's a matter of time before a TSO approaches someone in the restroom and insists on a bag and body search.