Today I noticed in my rep calculation a "-100 user was removed". I'm aware of the reason that votes on answers are rolled back if users who did the vote got removed. But that would account for only -10.
Now I have a single -100 line, which would either mean, that either
10 users who all did vote on one of my answers got removed at the same time (very unlikely)
I guess it could be that the votes were on a answer to a question of a particular user and got rolled back because the answer got rolled back
or
- There's a bug somewhere the Stack Exchange
The case (2) is somewhat counterintuitive. It would mean that questions and their answers got removed, (just) because a user got removed. Even if the user did violate the Stack Exchange rules at some point, this would be yet no reason to legitimate the loss of knowledge.