There is no consistent policy. This leads me to believe the procedures do not have that level of detail. This presents a major problem, since each little collection of dimwits can make up there own rules. Sure variability creates uncertainty for bad guys, but also creates vulnerabilities.

For example, ORD deliberately takes opt-outs AROUND the WTMD. What possible reason would they have to do this? Just because a person opts out of the NOS, doesn't mean the WTMD (a device that actually works for its intended purpose) shouldn't be used. How easy would it be to get passed the grope with a knife between your, um, ... never mind.