Rattigan - The Watchtower Sept 2012 states that the cry for peace and security was an initial sign.
"unlike mankind in general, we discern the Scriptural significance of current events. How exactly will this prophecy about saying “Peace and security!” be fulfilled? We must wait and see. Therefore, let us be determined to “stay awake and keep our senses.”—1 Thess. 5:6; Zeph. 3:8."
I believe the GB update that said not to look for the sign of peace and security was telling the JWs not to call it themselves but to wait for the GB to do it.
So the JWs no longer need to keep on the watch, all they need to do is wait for the GB to say the GT has started.