And how do you confirm all neighbours have agreed? What's the radius for neighbours? What about extortion to get neighbors to agree?

Status quo is much simpler - it's banned but if neighbours all agree have a late party and police aren't called

>Status quo is much simpler - it's banned but if neighbours all agree have a late party and police aren't called

How is that any different to what I just wrote? In your own example, the "What's the radius" and "How do you confirm all have agreed" is no different either.

because your rule is impossible to enforce.

I don't disagree but running around neighbourhood with piece of paper titled "permission to party" and asking people to sign it would feel weird.

This isn't a court, so no need for a paper trail. Rules are already like this in many flat complexes - I'd say most even, here in Denmark: No loud noise after X except with neighbour permission. Silence after Y.

Right till neighbour changes their mind and pisses on your verbal agreement and you have nothing to go by.