The bold portion of this quote I disagree with. Why should you let the officer know you have a weapon on you and alarm him further? He won't know and will not know unless you tell him or he searches you or your car, which you have a right to refuse. (yet you must remain cooperative, any issues need to be handled outside of this situation)
This will diffuse the officer or at least keep him calm, and if you have a ccw or open carry put your hands on your dash and explain to the officer that you have a weapon on you.
I view it as one the key CCW rules, which is never tell anybody that you have a weapon on you.