I saw that story in our paper this morning ... thought it was odd that they would be announcing this so openly. Why do the police have to telegraph their plans?
OPINION:
When these in-your-face announcements happen, whether it's from LEOs or the military; a specific, direct message is being conveyed to terrorists and/or would-be terrorists as to what the first step is that is being taken to prevent terrorism.
The implied message is IN MY OPINION, that if you mess with us, we'll go to step 2 and you, terrorist/would-be-terrorist won't like it. Bottom line, the message gives terrorists/would-be terrorists/general criminals something to think about.
As for the general public, this direct message announcement should make the common citizen more aware of their surroundings and is a reminder that the potential for terrorism still exists.