In Alfie Kohn's UC parenting method, my understanding is that when children want to do something which challenges your notion of what is "normal" or "right", you have a really good think about whether it really is a problem or not. And if it is a problem, then you make it clear that while that thing is not ok to do, you still love them unconditionally. So the mode of discourse isn't the kind of rewards and punishment thing where parental approval and love is connected, either explicitly or implicitly, to the child's behaviour.
I may be confusing the matter somewhat because I am not a UP parent, but I see that whole authoritarian trump card as making the whole method just a touchier feelier version of the conventional discipline paradigm, which I don't buy into.
Me, I think that when our children want to do something that we initially think "NO!" to, the best options are
1) to persuade the child, verbally or non verbally, that they'd rather do the thing you had in mind
2) to re-examine that "NO!!!" and see whether it really needs to stand and, if not, to back down
3) to work with the child to find alternative possibilities that both they, and we, and whoever else is affected by the action, are happy with.
4) and if inspiration fails, either the child wins or the parent loses, or the parent wins and the child loses, and both those outcomes suck - there isn't anything to choose between them morally.
It sounds all so convoluted written down like this, when what I'm really talking about is something like
Mum: "D'you want an apple?"
Child: "no. Chocolate".
Mum: "Hmmm. We don't have any. Banana?"
Child: "oh ok". or maybe "let's go to the shop and get some chocolate"
Mum: "Hmmm. It's only 6am and the shops aren't open yet. Shall we make chocolate cake instead with cocoa powder in?"
Child: "oh yeah"
and everyone is happy. Covered in flour and cocoa powder but happy.
I also believe fervently that the more our children get accustomed to the fact that we are not trying to thwart them, that we are trying to help both them and us and the people we encounter to be happy in our interactions, the more they trust that on those occasions when we say "I'm sorry, I just can't get you the moon on a stick" that we really cannot alter the laws of physics for them, and that we understand their disappointment and that we will do our best to help them find other cool things on sticks, also that we aren't stopping them from reaching for the moon, it's just that we can't reachc it for them, and not because we don't think that's an "appropriate" thing to do, or it's just "not ok" or it's "bad" or "naughty" or "silly".
Although I do think that the UP method might have a lot of merit, I still think there's so much leeway for someone to say "ah well, I'm UP but X is absolutely out of the question" when X might well be something which needn't be out of the question necessarily, like going out of the house in pyjamas. There is an escape clause for us parents not to re-examine our entrenched theories. I think one of AK's examples was that children simply mustn't have cake before supper. To which the answer from some might well be "er.... why is that a self-evident given, Mr Alfie? Why can't supper be cake on certain occasions? Will the world stop spinning? Will the FTSE fall to a record low? Will our children's legs fall off?"
I totally agree that "children need to be able to engage with society in a way that is acceptable", and that's all part of the guidance that we should be offering (and do offer, of course) our children. I think to say to a very small child "oh no, we just don't do that, let's think of something better" is perfectly acceptable - it's not that the behaviour is wrong in the abstract necessarily, but in the current context it is going to make all sorts of people uncomfortable, so let's not do it. And doing it might well mean we don't get invited back or we don't feel comfortable coming to this place again. I also think it's important when we are complicit in stopping (or attempting to stop) a child do something because that's the rules of that particular place, to make it very clear where the rule is coming from. "That's not our china cabinet, and Aunty Mavis says no thankyou, please do something else". Or "the librarians say no thankyou to children ripping up all the books" or "Gran says please don't draw on the walls of her house, but we can draw with chalk on the walls outside if we want, or we can wait till we get home". Ownership is an important concept to be learning early.
It can all be done without being set boundaries, just the circumstances in which we find ourselves - exactly the same as the moon on a stick e.g. I gave before. And if the child is determined to go ahead and do it anyway, well then the parent has the choice of going with that and dealing with the fall out, or stopping the child and dealing with the fallout, or suggesting something everyone would prefer.
I think the big distinction between TCS and the UP method is more one of mental approach than necessarily of how it looks from the outside. This is kind of duh, but if a family are walking happily chatting along the street talking about what they see and not running into the road, as you pass by them, you have no idea whether the children are not running into the road because it has been drummed into them that running into the road Is Bad, or whether the parent just had to say once "no running into the road rodney!" or whether they did the whole science experiment bit around it, with watching cars go by and feeling the big wind, and seeing how big they are, and seeing how they totally mash up the coke can someone else dropped in the street, and being aware of how much they could hurt you. Or whether the children are about to step out idiotically into the path of a juggernaut because their parents have neglected to guide them in this matter. You just can't tell from the outside.
But there's a deep moral and philosophical difference between a parent who sees themself as a trusted advisor to their child, and one who sees themself as just a pal, and one who sees themself as needing to Teach Their Child Right Behaviour by force, threats and punishment if necessary, and one who sees their child as a little prince who can do no wrong etc etc. And I haven't even touched on the ways that I'm sure most people would conceptualise their roles with their children because silly stereotypes are much easier to categorise.
There also is a huge difference between the kinds of things one does in one's own home and the kinds of things one imposes on people outside the nuclear family, and children are very very quick to pick up the idea that different actions are appreciated in different places. In one place, the chalks are used only on a blackboard. In another place, they can be used on paving stones. In another, they can be used on external house walls or in the bath or internal house walls or wherever it might be. But when our children are very very keen to do something and it is only OUR judgement that that's not the right thing to do - noone else is involved and noone else's property is involved, then those are the moments to be thinking really carefully about the likelihood of us parents being wrong.
With very small children, I see a lot of the parental role as being to guide children in multi-person interactions so that everyone stays happy - running a lot of interference - and then as they get older, they get the confidence to manage more and more complex social interactions without an interpreter and assistant (as if they are learning a foreign language, which much social discourse is, of course, when you are 0 years old)