If you need a system for education/training, there're dedicated platforms exactly for that, including Qualified from the creators of CW. At the very least, you could create a regular kumite and let your students work with it (they will be able to see the random tests and the reference solution, assuming you implement those, though). Authoring a kata means making it public and a subject of the kata QA process; having your friends, colleagues, students etc. blindly upvote it just because you know each other is interfering with the said process at best and spam at worst.

We didn't know, that upvoting in beta-state would cause such a reaction.. we thought, it's kind of feedback for me (the Trainer) to see whether their (almost identical, agreed) code runs through

The website is not really self-explanatory at this point - no hint, what "beta" exactly means, nor how the publish/review process will work and what we may do and what not, sorry for that.

Our "clan" consists of two Trainers (Code-Diva and me) and five students.
We made this kata as part of our C# education with the students and wanted to share it with the community.
Yes, we all were together in the same room, we developed it together (for their education).
I hope this explanation is sufficient.

Testing insufficient for cheats on almost correct hacky code...

miracle

Christmas! :D

Gaming the system need not surprise anyone. Nor does ( quite charitably named ) 5-tuple programming ( ie. pair programming for people with four actual friends ).

Practically a duplicate of this kata.

Also, 4 people from the same clan as the author passed the tests with pretty much the same solution, and everyone immediately voted very satisfied. Could you people explain this miracle?