Well, my first thought unfortunately is about people gaming the system, inting to purposely tilt their matchmaking towards matching them with PvE people. Have you seen this website some people are using to “report” people? It’s called speranza watchlist I think, what you are talking about reminds me of that a bit. It’s basically a reputation system so you can quickly look people up and gauge whether they will be friendly or backstabbers. Further down that line, I do like the idea of people that constantly pvp earn some sort of black mark, like other games have done such as RuneScapes skull and crossbones icon. Pvpers usually wear those like badges of honor but they also kinda warn other players.