Gewoonterecht (not quite the same as custom law, but close enough) and gedoogbeleid (something very Dutch apparently) were two completely new notions to me when I came to the Netherlands as a law student 13 years ago.
To put it in a very simplified manner: gewoonterecht = everybody does it this way; gedoogbeleid = nobody ever gets punished for doing this. It didn’t take me long to embrace these two concepts. For me they represent freedom, pragmatism and overall sanity so typical for the Dutch society.
Some time ago I have received a fine for parking my car on the pavement. I spent six weeks making photos of my neighbours’ cars parked on the same spot. And today I used my favourite legal concepts to protest against the fine. In my letter I basically said: look at the pictures – everybody does it; you haven’t punished them so why punish me. Let’s hope it works. :)