Just to help people be Dan Lkaf Zchus a little and understand, often there are children who really are too young to be quiet the whole time, but they already go to school/ preschool/ gan and have learned all about listening to the megilla, made their graggers, etc. Parents are now put in the position of having to tell them they are too young to come! Some parents just hope things will work out, with the results discussed above!
In my old neighborhood they addressed this issue by having a “kids megilla reading”. The Bal Korai at this minyan would lein about half of the megilah, for kids. It was not to be yotzei the Mitzvah, but to give them the opportunity to come to shul, listen to part of the megillah, shake their graggers, etc., without disturbing the real kriah.
Maybe this idea can be adopted in other places!