Using an empty foreign construction plot "just like that".

It only becomes problematic when, for whatever reason, stuff is in the way and not cleared away in time. For example, because the neighbor was stingy and the construction worker from elsewhere won't come for the next two weeks. Or the shaft breaks and no one wants to admit it. Photos of the license plates won't help in that case. Or a truck leaks oil.

You don't need to ask for minor underground stuff, but for bigger actions, I find it cheeky. For example, a crane on someone else's property without asking.

I would find it legitimate to demand that the neighbor fences off your shafts to prevent damage.

But when our neighbors started, none of the neighbors knew each other yet. The contractor just went ahead. Often everything refreshingly unbureaucratic on construction sites. I wish it were like that at work sometimes.

I’m happy! Refreshingly straightforward! In general, that way you get to know each other better, after all, you have to work together later. The neighbors can’t help it, it’s the contractor! I can only speak for myself: on my construction sites I always ask beforehand!!!! If there are curbs, manholes, etc., I photograph them beforehand. It’s simply part of good manners for me. I would occasionally talk to the site manager about it, so that it "clicks" for later as well.

My brother spoke with the foreman, who contacted the site manager, who in turn called my brother. Then he first "gave the site manager a piece of his mind" for using the property without asking.

The site manager, quite meek then (he is apparently also the client and thus almost our neighbor), apologized properly. Likewise the foreman. Now everyone is happy because the crew has received permission (each time after a brief consultation) to park, for example, another truck with roof tiles there next week. All trash will be disposed of and if anything breaks, of course, it will be repaired.

They are now keeping as sharp an eye on the property as a lynx (so they don’t get into trouble later and kindly informed us today that from another construction site diagonally opposite (plasterer) trash has been dumped at our place (cement residues etc.)

They now have a deadline until tomorrow to clean it up properly (when addressed on site today, they just said "we always do it this way")

I would talk to the future neighbor and say that it basically doesn't bother you, as long as it is not to your detriment and any traces are removed again.

I basically don't find it bad either, but I would expect that one asks beforehand if it's okay.

I would handle it the same way -> Simply introduce yourself and clarify in the process that it's okay as long as everything is left in good condition and possibly announce when it will start for you personally ... Nevertheless, anyone can inquire at the municipality or whoever the properties previously belonged to, whether they might provide the contact details of the neighbors or leave their own contact information to get in touch and ask. "One doesn't know each other yet" is, in my opinion, not a valid excuse. Good luck

that someone from another site diagonally opposite (plasterer) disposed of rubbish at our place (cement residues etc.) [...] "that's how we always do it"

... until they build somewhere where someone "always does it that way" to teach them a lesson for that saying

Our neighbors opposite have turned their 2 building plots into an English lawn ... the green looks better than my turf .... if someone stands on it, they go berserk, I tell you ... not even the children are allowed to play on it