When you take something from "permitted" to "restricted", you turn actions from "normal" to "suspicious", and that definitely acts as a signal for observers and

When you take something from "permitted" to "restricted", you turn actions from "normal" to "suspicious", and that definitely acts as a signal for observers and a deterrent. The FAA requires airline doors to be secured. Why would you assume that does nothing to stop a domestic terrorist? I can't imagine why you'd even say such a thing.