> If your party is successful, the police will knock on your door, unless your party is very successful in which case they will lob tear gas through your living room window.

I threw a party (illegal, on the beach, with great music) so successful the police just provided security at the parking lot entrance 1km away because they didn’t want > 400 wasted people roaming the affluent neighbourhood if shut down. Oh there were also nudists at the beach when we were ferrying in our gear at sunset who stayed for the whole thing and ended up on the dancefloor in their birthday suits at 2am.

Having a lot of partying people at a place, combined with sensible policemen, is the best recipe for not getting busted. Had that at least twice in my life. Once at a house party with a lot of young, just around the driving age, people. Police showed up, and decided to not bust it, because sending people on the road would be more dangerous then letting things just go on. A few years later, I was at an illegal outdoor tekno party, which also got a visit at 8AM by two policemen. They basically just went up to the DJ and sayed: "We will return at 3PM, and you will be gone."

My Finnish gf told me that the police in Finland is so reasonable and human, that often they will stop by just to check in if everyone are safe and well and if anyone needs assistance. She mentioned countless of times she was with her international friends partying, or doing sauna or skinny dipping in the lake, often all the three things in the same night of course, when her friends got nervous when the police stopped by, and she was like "ahh no, don't worry, they just want to check if we are all okay".

Police asked if they are all safe, nodded and wished them a nice party.