I think it's useless. Servers are privately owned, thus they should be allowed to moderate however they see fit. If people don't like how they operate, then they don't have to play on them. Most servers already did this, so implementing the report system is completely useless and it can easily be used for false reports. Also, I don't like the fact that you have no idea who the reviewers are. The message doesn't necessarily have to contain anything explicit, but if the reviewer deems your message to be harmful, then there go your online privileges (which shouldn't be something they can do, as I previously said, since servers are privately owned and operated on their own hardware, not Microsoft's or Mojang's).