What is the point? If you look at the 3 month activity of the top 3 polish learners you can see they simply auto knew on page completion, virtually no lingqs learned and the words learned vs read would make them all savants.
A challenge is useless and demotivating if things like this are allowed to influence rankings, it also is an insult to the 4th place on the polish board that you can see put in real work.
The whole life is an insult: you live and you know you’ll die one day. Not to mention the pain in between. So… try to take it easy.
We all know there are cheaters. Maybe they have late stage cancer and this is their only way to get some appreciation. Maybe they are 10 years old only and have a very different view of fair play and well earned effort. Maybe they just want to make you angry, for fun. You can never know who’s on the other side, behind a nick.
Polish team won. I don’t think they used any tool what we could not use either if we wanted. So, my congratulation to the Polish team!
Et allez, allez l’équipe de la France ! 
You can also compete against yourself. Hard challange can be really hard depending on your level. It can very satysfactory to simply complete it. I have used for extra motivation to go a little further. When you think about it, there are activities what are not rewarded. For instance, if you read a second time a book you won’t create LingQ. So uour linkq creation stat will be low.
So your argument is that because anyone could cheat that it doesn’t matter. The extension of your argument is that if someone breaks into your house and steals your stuff it’s ok because you don’t know their circumstances.
You completely missed the point being made if there are going to be group or community challenges there needs to be some sort of auditing. The end result of allowing behavior like this is the community will stop participating. If the creators actually want to build a community on their platform they need to take it seriously, if it is just an empty placeholder for advertising then just let it be. It all depends on what they are trying to build.
@shawn12 We can’t really control how users are learning, or prevent someone to join the challenge for moving words to known on lesson complete screen. I understand what you’re saying, and we do have in plans to make some improvements in the future.