It's a deeper problem than just being about corporal punishment, it's about respect.
When I was a kid, I was taught respectful behaviour both by my mother and my teachers at school. These days, with so much in society geared towards kids, the notion of respect for oneself and others has gone out of the window. I certainly don't advocate corporal punishment in all cases (indeed my father used it excessively and without warning on me, causing more damage than good), but some sort of deterrant is needed.
Personally, I feel those diabolical teenies who go around breaking into cars and homes without fear of prosecution should either be sent to boot camp or publically birched. Either way, the notion that one's actions have consequences must be brought home to them in some way. After all, within ten years they may have children of their own.
Society needs to preserve the rights and wellbeing of children without resorting to hysteria. Corporal punishment (ie, a short, gentle slap across the buttocks) has been used for countless centuries, but now we're supposed to use other means to discipline our children.
For example, I've two neices aged seven and four. Normally I absolutely adore then, they give so much unconditional affection and bring smiles aplenty, but they do have their dark sides.
With my eldest neice, I've been able to reason with her since before she could walk. Taking the time to explain why she mustn't do something would work more often than not, thus avoiding harsh words.
The youngest is a different matter, everything you say she mustn't do becomes a challenge. If you say no to her, she'll do it anyway and she simply won't listen to reason. Sometimes a simple hard stare will stop her, other times you have to make a threat (ie, go to your room etc) and carry it through. Backing down in front of a child is a sign of weakness that they'll exploit. Each time she misbehaves when I babysit, I explain to her that it's her choice whether I stay and read her a story, or send her to bed immediately, depending on the course of her actions.
With both, I always try and instill some respect. Yesterday they came to see me and Hannah (eldest) said:
"Playstation!".
My response was simply
"Pardon?"
We carried this game on until she managed
"Uncle Paul, can I play Playstation please?"
My brother seems quite happy for me to take some disciplinary responsibility while they're in my care, and although I love them both to bits, I believe that fundamental things like good manners and respect are vital skills for any child to learn.