For too many years I (basically) ran an Unsafe Space/Squat/whateveryouwannacallit, in my parents house, for the time that I was in high school.
We had our core group of 12-15 on a daily basis, and on party weekends/weeks the numbers often got upwards of about 100, but I knew the Lions Share of the attendees at the time.
The rules were simple, easily followed, and enforced by everyone. If a new person showed up, they learned the ropes quick enough. Dissension was dealt with decisively and swiftly.
We all had a good time, nobody got injured beyond what a bandage or a bottle of Pepto could take care of, nothing got broken or stolen.
We even had a cigarette box for those who ran out while there, as well as a condom box (for obvious reasons), and even a feminine hygiene box if it became necessary.
The cost? BYOB/D, Bring your own food, The House pays for nothing for and during the party.
TL
R version: It's a simple, yet complex thing to operate an Unsafe Space. As long as most of the people assist in the successful operation of all phases, you're good to go.
Good grief I miss the 80's...