First in regards to parents and children. While I am glad we have moved past the severe lashing and beatings that we hear about from previous generations, I think things went just a scootch too far in the other direction. I have no problem with a parent spanking o smacking a child in a "controlled" manner. You cannot do it out of anger, or other emotion, it has to be a last resort in negative reinforcement to change behavior before it becomes completely ingrained. If you let a child get away with something long enough that it gets instilled, trying to beat it out of them turns into abuse. I guess I would rather see it eliminated completely, rather than go back to the way things were in the "old days", but used judiciously, and without malice it can be a very important tool.
I don't remember my parents ever hitting me (I am 43), but I knew it was an option (mostly because they did it to my younger brother). With my own kids, I know I gave them each some smacks to the hands if they insisted on grabbing or touching something they could no; though my youngest finally getting to touch the hot burner was a bigger lesson to both of them than the smacks, to bad it cost an emergency room visit. I also know that I would very occasionally give them each quick smacks on the butt, but I don't remember any specific details.
The key is is that the parent has to establish themselves as the Alpha in the pack or there will be dire consequences later on. Sometime that can be done without any corporal punishment, sometimes it cannot.
Now to go even more controversial: I am from the US and I believe there should be more corporal punishment in the justice system, and a very large reduction in the inhumane warehousing of humans. I would much prefer to see non-violent and "victimless" crimes punished by a caning and letting them go on their way, rather than just shoving more people into overcrowded storage facilities where they learn nothing more than how to become better criminals. I don't see how this can go much further here, without getting political, so I will stop there.