... out of fear that the neighbor says "njet" > the security cannot be provided > the safety coordinator sends everyone home ...
(the vacationer herself presumably has the experience that neighbors very rarely object in such cases).
That is exactly why I do not understand the whole matter. If the neighbors have to agree anyway, the vacation representative could have simply called the client briefly and asked him to go to the neighbor with "such a note" to inform him. As far as I have understood so far, it is just a formality and could have been taken care of the evening before the setup, maybe even early in the morning before the setup, with plenty of bows and maybe a few euros (for the children/grandchildren?*). It is clear that this would not be very elegant, but I think almost anyone who has ever built something themselves understands such constraints.
That is why "one" does not stop such, from my point of view, a major project on which many other things depend. I do somewhat think that the assembly team may have been needed elsewhere and the vacationing construction manager could not represent the client’s interests due to absence. Or at least no one was there who, sufficiently motivated, creatively looked for solutions in the interest of the client.
However, as always, I look forward to the assessment of the forum members who are more knowledgeable and know more about such proceedings.
*I always give craftsmen money for their "coffee fund," other people "pocket money for the children’s/grandchildren’s piggy bank," even if they are already grown up. Usually, one then laughs together and exchanges stories about the children. This way, I avoid giving the impression that I think the other person urgently needs to accept money from me. ;-) Anyone who has children/grandchildren knows that it is always welcome to put something into the "piggy bank."