How do you deal with established users who have gained reputation, badges and privileges by illicit means?
This might seem silly but it has real world applications. Things like this, where >1k rep users do something really quite wrong, happen a couple of times a year. Dealing with it smoothly is important to the continued success of the site.
You are a moderator. A community mod from Stack Exchange comes to your mod-only chat room and tells you the news:
We've been working on the voting fraud mechanism and. We have worked outdiscovered that three of your highest rep users, Oli, fossfreedom and Luis Alvarado have all been using a carefully hidden network of sock-puppets to boost their reputation for years.
They have cheated the system out of Hundredshundreds of thousands points of illicit reputation reputation.
The system is certain they are guilty and there's no way they weren't aware of what was happening.
When confronted Luis was the only person who admitted there was a system in place and he also points to the others' guilt.
- Banning them or doing anything "too harsh" could mean they leave the site forever.
- Doing nothing, or being too lenient might show newer users that they can get away with stuff like this, as long as they're good at it.
What would you suggest happens next?
I know there isn't a single best answer —and your opinion may change when faced with it in reality— but I'd like to get the measure of the prospective moderators, at least how they feel they'd handle this if it happened today.