Without all the information you're still left with a lot of mystery. I might ban an account, for seemingly nothing, because I can see they've created 15 accounts in the last two days to troll and stir shit up. Partial information seems to create as many, if not more, conspiracies than no information.
I think any action done can be noted to that effect, but a step towards transparency should be a goal, because over time and interaction that “mystery” cold be solved. Wikipedia records all changes for review, with such an erudite crowd behind HN, it would seem trivial to establish such a system.
Moderating large social systems is tricky.