MrFish,
I don't have a problem with any parent who feels that it is appropriate to spank thier young child. I think it's a parent's right and obligation to discipline thier kids.
I don't spank my kids. I don't believe it's necessary. Maybe I've just been lucky with my kids (all fairly well-behaved girls).
However, its been my observation that incidents of hitting, spanking, and whippings of children become more frequent the lower down the socio-economic strata you go. I stand by my statement that many, if not most, of the convicted violent offenders in jail or prison have been subjected to physical parental violence. I have no way of proving that they have, its just my impression. I have no way of proving that being subjected to this violence as a child causes a person to be violent in later life. But it seems to me that a child learns how to deal with anger from its parents. It is obvious that these felons have problems in that regard.
In your example of the woman and her daughter on the bus, its pretty clear that the mother had no control over her child. I'm suggesting that the mother didn't lose control at that moment, she lost control over her child long ago through lack of discipline.