The characters are all supposed to be from Switzerland. It is even established that they're from Zürich. But none of the characters speak Swiss German in the movie. They all speak Standard German, which is a dialect-free version of the German spoken in Germany.
The place where the group of protagonists meet up in the beginning of the movie, set nicely at the shores of lake Zürich, is actually not only a strict no-parking area, but also not really accessible by car. It is possible to drive there, but there are so many obstacles such as a patch of grass, benches and trees.
