how you think why Egwene has a problem of drooling(KoD prologue), but Liandrin and other BS in а similar situation haven t it(FoH 18)?

 Why take chances, for one its intimidating and another is there is no way to betray the others.  Verin did say darkfriends can betray each other and even turn against the chosen if they can justify it.  Moggy simply took no chances and also is there a circle of silence weave?  With that there is a risk of the circle being off and someone hearing.  Moghy way there is no way any of the BA there could betray anyone if captured, another forsaken grabs them, or they decide to grab power.  I think she was just being extra cautious. 

I m sure you miss one fact in this case!  The BA can see, how Moggy speaked with their sisters, and it s possible that 1 or more of waiting BA have the skill-reading by lips. If Moggy "extra cautious", she must take it into consideration and to realize more defense than gagged mouths and ears of Lia&co