I quite clearly noted that it could occur like you mentioned, but as possible as it is, it's also very rare.
Most injuries - the vast majority of injuries - are accidental, and I believe that a lot of these people who intentionally want to "rip your arm off" aren't actually trying to rip your arm off, but rather train with more aggression and more intensity than you'd like.
I have never trained with a person that has intentionally tried to injure others. I have trained with people who apply submissions quickly, and people who are generally just less pleasant to roll with than others, both of which can be easily be solved by tapping early and often, but never someone whose sole intent is to injure you.
So unless that is the very rare case, no. I wouldn't blacklist someone like that.