Why would you yell to the person sitting directly behind you?
Turn around and speak normally.
I find that "silent communication" is childish, no matter how effective it may be. I think it teaches the child a wrong way to deal with problems.
In the case I was referring to, the miscreants were back and across the aisle. I would have had to let the whole FC cabin into the conversation, which I chose not to do.
You have your preferred means of communication, and I have mine. Most children above the age of 3 know they're doing something that is not acceptable. Your assertion that it's
childish to give a stern look at a child who is misbehaving is ludicrous.