Interesting thread
My youngest is only 3.5, but I wouldn't say I punish. Luckily, I don't really need to as generally she's well behaved.
I am, however, strict. I'm a primary teacher by trade and she's well used to the hard stare, the "I do NOT expect you to do that again do you understand?", the countdown from three etc.
So I suppose I front load - when we are going to somewhere eg to a party I will discuss correct behaviour with her in the car before we get there. I am then eagle eyed whilst we are there and any poor behaviour, by which I mean not saying please or thank you, pushing, not sharing etc is stepped on. Afterwards I will praise good behaviour OR if we've had an issue I'll talk about it afterwards and why the behaviour fell below expectations.
I sound quite Victorian. I probably am, but I'm not the most patient and I have high standards.
As I say, she is generally very well behaved. Whether I have created a well behaved child with my method of bringing her up or whether I am lucky that she is generally "good" and responds well to instruction, who knows? No one has the "control" child to show how they would have turned out if you'd have done anything else.