As you say, batters and scummymummy, it's so important to explain to a child what it is they are doing bad. Sometimes I too feel like a cracked record! I also like to make the punishment fit the crime: ie cleaning up the milk they spilt. I know that you have both got younger children than me, but here's what CAN happen when I try explantion on my 7 year old.
PS I realise that neither of you are saying you only explain without resorting to any other punishment.
When my son is being at his devil child worst (this happens five or six times a year) he will smirk when I tell him how upset mummy is that she's got to clean the kitchen floor again etc.
Saying 'I am sad, I am worried, I am disappointed because.....' brings attack of 'attitude' and dumb insolence, with a bit of name-calling thrown in for good measure 'stupid lady' is a favourite. This is a critical danger point for me. He is showing open disrespect for me. It is so tempting to give a single short smack, and yes, I freely admit it, to exert my power over him. I make myself use words instead, and firmly tell him to go to his room. But he refuses and still smirks. He weighs six stone, so there is no way I can carry him up the stairs. I might resort to a threat to phone daddy, which he hates, or his headmaster. This stops him in his tracks and I can then make him go upstairs to cool off. I hate making this threat. Bringing daddy or another adult in sends out the message that mummy can't cope.
So.... I have learned to cut the explanation if I sense the situation will escalate this way. Paradoxically, an ignored explanation makes tempers on both sides rise too much - increasing the risk of a smack.
I have found that rewards and the taking away of treats work far better for us. Usually my son is only too aware of how, why and what is wrong with his naughty action. Any further explanation happens when we have both cooled down.
I've been following this discussion without having the time to post. Just two further things to say: Jasper,I think you are so right about there being different definitions of smacking.
Also, lots of people have said isn't it illogical to smack a child for smacking another? What sort of example are you setting? Isn't the other side of the coin as follows: you are showing a child exactly how horrible it is to be smacked ie making the punishment fit the crime? Not saying this excuses smacking, just saying there is more than one way of looking at it.