Give voices for unjust / unfair banning or suspension
Considering the blacklist of users can be shared to other channels, it is highly possible that it can be misused and lead to unjust banning or suspension by the channels that are not related to users' past offence. This is discriminatory treatments for those users, and it is unjust. An example is suspension of users due to racial or sexual slurs, while the streamers are the one who say it first or goad the users to it.
And what if from the start those users were banned or suspended unfairly, and their past "violations" are still recorded in that list? Even in this forum you can see examples of it, and that's not a good treatment for those innocent users. For example, banning bots, while the users aren't bots.
The solution is to give option to counter-report the channels that falsely ban or suspend the users. This should be outside the appeal system, and the channels should give proof that their allegations are not false. Burden of proof is for the accuser first. Next, give the users the opportunity to refute those allegation and give counter-evidence. Twitch then publicly decide which side is right and keep a public record of it, so all users and channels can see and learn from it.
Moreover, since there is record for users' "past violations", with this there should be record for channels' "past false allegations", and it should be viewable by users. And there, it is fair and just.