So, this would be my suggestion:
1. Instead of submitting a post, a user can request to get it preemptively approved by mods to prevent it from being flagged
This can take some time, so one downside would be that there would be a delay between the request and the post being visible in the forum
2. If approved, the post stays up no matter what - users can brigade and flag all day long, but the post was already cleared
3. If not approved, the post goes through the normal cycle
Does anyone have a better suggestion to reduce the negative effects of users who misuse the flag/report functionality?