It's reasonable to understand that past certain numerical thresholds, people stop being individuals and they become masses. And just on laws of averages they're going to get increasingly messy.

Yes, but there are many large assemblies, even presidential inaugurations exceeding a million people don't get unruly. Is there evidence they would be messy like you said were it not for policing?

MIB? Nice quote but in my experience I have observed both. I have seen multiple videos in the middle of BLM protesting and rioting where the crowd protects a cop to safety in the middle of cops dismembering protesters. And there was jan6 when they killed cops.

Depends on the person and the crowd! And their state of mind. A panicked crowd is ad irrational as a panicked individual, except their actions are amplified by their numbers. There are a few who act on their own and the masses who follow along because they think the crowd knows best.

I have been in traffic jams, get curious and take a random residential road trying to find a way out, and like 5-6+ cars follow me, even try to loose them and they follow me to a dead end street lol.