Actionable advice, thanks folks!

Thinking over last night's (exciting!) discussion it's become apparent the girls really think "Nachtruhe" really means "just a bit quieter, come on it's Friday/Saturday". One of the nicer but very drunk girls confided they view this apartment as their chance to get a piece of the good life (paraphrasing), and their expectation is frequent parties. So OK, so we'll try but unfortunately I don't think it's a misunderstanding.

Do you see any value in the Verwaltung route? Or is the occasional fine our best bet in change behaviors?