I lain Megillah in a large shul every year. I can tell you that, as a ba’al kriah, I hate disturbances of any type, including that of children crying. Part of the problem is that I have to balance the needs of the k’lal against that of individual people.
I don’t want people to miss the opportunity to be yotzei the mitzvah of Krias HaMegillah. The problem is that if I stopped (and went back) *every* time I hear a disturbance, the Megillah laining would take hours. So that means that I have to make a judgment call on whether to stop and go back or not.
The result is that every time I lain for the tzibbur, there are, undoubtedly, some women who were not yotzei, since I can’t *always* go back (and there are also, no doubt, some disturbances that I don’t hear but, nonetheless, cause people to not be yotzei).
The Wolf