I'm not very involved in the topic, so my POV might be very wrong - but most effective enforcement, from my overall life experience, is having someone act as a

I'm not very involved in the topic, so my POV might be very wrong - but most effective enforcement, from my overall life experience, is having someone act as a "bad guy" and sharply deal consequences to the people that behave like assholes. I feel that having a detailed COC, while a very good sentiment in theory, in practice must bring about people who will try their best to skirt around the edge of COC and make trouble for the maintainers - who I expect want to stay "nice", but they're forced to act harshly in the end anyway.