We have to find a solution for this problem because it has become very annoying.
I don't really know how to solve it, but maybe we can do things like: Block the cheater's account forever or prevent him from participating in the next 2 or 3 rounds....
We must seriously think about it, There is definitely a good solution to control this problem because it is unbelievable when you see a Pupil or even an Expert account submitting 3 problems in the same minute and getting Accepted in all of them Even the great tourist can't do these things، and of course there are many other examples of cheating by some contestants....
At the end a huge thanks to MikeMirzayanov for great systems Polygon and Codeforces, and I'm sorry about this blog, but I love codeforces and I don't like this stuff on it and hopefully there will be a good solution soon.