The cops in question were apparently local members of a Joint Terrorism Task Force. They get these tips from "the government", check them out, the people are once again not terrorists, and they then talk to them freely like normal people, because (1) they are and (2) the cops aren't NSA, don't have training in this kind of secrecy and don't care, and (3) do pretty well by classifying people into sheep and goats without worrying that some of the sheep might be cleverly disguised goats or have goat friends.

So yeah, this part of the story is entirely plausible to me.