I have to respond to the fractional sweets thing.
My partner’s parents (her dad mostly) enforced an 8-point rule around candy. One m&m = 1 point; 1 starburst = 4…
The consequence? She developed an unhealthy relationship to candy and would binge on sugary garbage whenever with friends whose parents did not enforce the rule. She didn’t get a chance to discover her own limits for herself.
Contrast with my upbringing: there just wasn’t candy in house, and my parents were relatively relaxed outside the house (granted breakfast was still garbagey cereal but standards change). I never had a problem over consuming candy.
I guess the takeaway is that (human-)enforced moderation is much more fragile than passive (environmentally enforced) moderation.
But then, if I consider how different our siblings are from us (my brother has way more of a sweet tooth, and my partner’s sister had less of a sweet tooth than her), I’d have to conclude that none of this matters, kids are their own creatures, and everything I just wrote only counts as the weakest possible kind of evidence. Oh well.
Yes, I think it varies a lot between people. Comparing me and my two siblings, one has a very strong sweet tooth and always wants to eat lots of candy, one sets rules for themself about how much is okay and doesn't have that much, and the third isn't that interested.
I fully second this approach. It is very close to what we do and has worked very well. The oldest of our four boys is now 18, they have three parents, two homes and probably a dozen contexts from parents, grand parents, friends to school that they are comfortable in.
We do it exactly the same in all accounts - context is important and kids are perfectly capable of distinguishing those from a very early age on (and I had many discussions with relatives, who doubted that).
One thing to add to the "who supersedes who" when multiple adults are present: We had the additional problem, that my wife and I do have different styles of parenting as well and while we tried our best to harmonize them, there are some edge cases, where we handle things differently. This lead (and still leads) to some stress, because if both parents are present, every situation with the kids is more ... noisy? The kids express more energy? IMHO, this is due to the problem of context: which parents' context to follow now? So from the kids' view the situations' context is ambiguous.
We introduced the rule, that if one parent starts to ... parent and starts solving a situation, the other parent must shut up and not intervene at all. The parent who started handling a situation also finishes. If the other parent disagrees on how this situation is handled, they still shut up and we sit down later without the kids, talk about it and try to harmonize our approaches.
That greatly reduced the stress with (and in) the kids - they (and we) have a predictable context to follow and are less stressed from the context being ambiguous.
The "one person parenting at a time" rule sounds like a good approach! We do something similar.
They were pretty sad about this. After some thinking, Lily decided to ask Ricci whether this counted as a "Ricci adventure", and he said yes, after which she asked if this meant they could have ice cream. Rick confirmed with me that I was fine with it being his rules, and the kids were happy to have ice cream.
That sounds like a good exercise to deal with modern bureaucratic systems.
It's very common that there are multiple adults in a child's life who parent differently. These can be explicit differences in rules (I allow jumping on the furniture, you don't), or more subtle differences in approach (I'm fine with kids trying to persuade me something should be ok, not everyone is). Adults often get in conflict over these, and I think this is generally not worth it.
There are two main reasons I've seen for parents wanting others to take a specific approach with their kids:
You want consistency. I'm strongly in favor of predictable parenting, where kids know what the boundaries are and can predict your reactions. Kids are smart, however, and are very good at learning that different adults/places/situations have different systems.
You want a specific approach. There are a lot of ways people parent, and they mostly work fine, especially in moderation. Perhaps the aunt lets the kids have lots of sweets, grandma requires shoes outside, or the babysitter won't take them out if it's raining. While these aren't the decisions I would make, it doesn't matter that much. Now, I wouldn't want anyone who looks after my kids to enforce discipline by hitting them, and neither would I be ok with someone letting them play unattended by deep water: some things do matter. But the conflicts I tend to see are over much smaller differences.
One place where this can be more of a problem is when multiple adults with different styles are present at the same time. I think the main thing you want is consistency: if the parent is present you go by their rules, or perhaps you go by the rules of whichever space you're currently in. This does mean that if adults are often ambiguously in charge of the same kids it's worth putting effort into harmonization: different parents having different rules doesn't work very well. I expect this to come up if/when our housemates have kids.
There's also the issue of cross jurisdictional precedent ("grandpa lets me do it!") The most common way to handle this is just "grandpa has different rules", and leave it there. This is fine, but in my particular parenting style I'm happy to get into the details if the kids want to. Why is grandpa ok with it? ("That much sugar all the time wouldn't be good for you, but you're with grandpa rarely enough that I'm not worried.") Sometimes I don't know why different adults do things differently, in which case I'll say so, and suggest they bring it up with the other adult if they want to learn more.
(Story time: when the kids go off with their grandpa, it is a "Ricci adventure" and it's his rules that apply and not ours. This summer we were exploring Wareham (MA) together and the kids wanted to get ice cream. Unfortunately, they had already had their whole before dinner sweet, with some kind of sweet breakfast. They were pretty sad about this. After some thinking, Lily decided to ask Ricci whether this counted as a "Ricci adventure", and he said yes, after which she asked if this meant they could have ice cream. Rick confirmed with me that I was fine with it being his rules, and the kids were happy to have ice cream.)