She can always say, "Thank you for the UNsolicited advice". I haven't had this happen to me in public, but I think I was just lucky. I have gotten plenty of stares as I removed my child from the situation, but I just waved to the curious strangers and that always stopped their staring.
What may work for one child, does not work for another. There is no "one size fits all" when it comes to parenting children, at least in my personal experience. Some children are more lively than others, just as some adults are more lively than others. As a parent, I try to parent/teach according to my child's temperament and personality, but it doesn't always prove effective.
One of my closest friends used to brag about how well behaved her DS was and what a great job she did teaching him how to behave. Her DS is a very quiet and subdued person by nature. Well, that fantasy lasted until child #2 came along, a girl. Let's just say that my friend used to call her "Kate, the wild woman". Since then, my friend has eaten quite a bit of humble pie.
I don't understand why some folks feel the need to approach a total stranger and proceed to berate them about their child's behavior. It's just plain rude and direspectful. Just as parents can remove the child from the situation, those bothered by the behavior can do the same.
I remember one time we were staying at the WL and decided to rent a tandem bike. DH and the kids picked out the bike while I paid for the rental. Two sour- looking women were standing behind me and kept staring as my husband and my 3 kids got into the bike. They didn't know that we were together and they must have assumed that DH was allowing the kids to play on the bikes. Anyway, they went on and on about how the father (DH) wouldn't tell the kids to get off the bikes and why he would allow them do such a thing. They kept shaking their heads and staring at them. I really tried to bite my tongue, but... I turned around and said to them, "Yes, that is my husband and those are our children and that is the bike that we are renting and I'm paying for". Well, that stopped their comments! When I walked over to my family and the bike, the women kept staring. I turned around and told DH what had happened. I waved to the women and said loudly, "Hello!". No more stares from them!
Maybe next time I'm standing in line at WDW and the person in front of me has really bad body odor, I will take the opportunity to preach them about their personal hygiene habits.

After all, I find it rather offensive!
