Providing information like MediaWiki's block list as to when, how long, and why someone was sandboxed or silenced, is something that would probably be quite helpful for !postActiv - even if an abusive admin will just not use it, or misuse it.  It also provides a canary in the coal mine for those kinds of instances (you can see they're not really taking care with that)  And for a properly-governed instance, it helps establish the fairness of these blocks.