How does a group decide what “acting up” is? Who is actually making the decision to kick them out?
When you have a group this is either large or long-standing, these questions eventually come up. I’ve been in a 5-hour-long meeting that was the 2nd of 3 attempts to eject a mid-30s non-student from a University student computing club. I fail to see how this sort of stuff is easy.
If you do, then have a meeting amongst the leaders to see how to reconcile actions with the charter.
Most problems occur when the dictator just wants to step aside and let the general population decide an issue, but there’s no real mechanism for doing so.
Generally speaking, this is caused by too much policy, not too little policy -- and adding an official code of conduct (which a university likely already had!) isn't going to solve that.
How many people? The first comment of that thread was talking about a 3-4 peoples groups. I personally agree that for large group you NEED formalities. It's not even a question of if it's better with or without, the group will just not survive without formalities.
What acting up? Did you felt right about how someone acted? That's acting up. Is it enough to kick someone out? That would be mostly about if he keep doing it or not... and how everyone else feel about it. Maybe it just means that this group isn't meant for you either.