It sounded more to me like she was trying to remove allowance money to stop the behavior.
That only works when you have a history of making good on the threat.

As for passing public judgement, a kid throwing rocks is a public nuisance. Furthermore, why are children "everyone's children" only when there is an override to be passed - the village works both ways!

Then again, when my kids get to the dangerous behavior stage, we don't whine about allowance. Dangerous behavior that won't stop = full nelson hammerlock time!

Yes, you can touch your kids to discipline them and even restrain them physically when they are a danger to themselves and/or others. It is NOT the same as hitting them.

Sorry to contradict your effort to give her the benefit of a doubt. She was trying to bribe dear little Ben. She was bringing out money. He understood the intent too; this clearly was the norm and not a first time.

I have provided allowance to my boys, provided in turn they do their expected chores. I contend that no parent should pay a child not to physically assault a sibling. Paying to halt bad behavior virtually guarantees that the kid repeat it for more cash. This was not Ben's first bad day. It was also pretty clear that he'd hold out and act out until he got the price he wanted.

She was whining and begging, and very much not in control. People who allow that kind of brutality by their young children, particularly in public, have to know civilized people will judge them.

By the bye, just in case you feel you have to defend the woman, my wife got the same read. She was just ahead, saw and heard it first, and was appalled. We concur on what was up with this.

This is from my observation and musing blog. If you want serious, head to Marry in Massachusetts.