Imo, what is… is fine. Clicking telegram link won't do anything, you can view content without actually following, signals are posted, results are also.
Because he will control the content, he can prepare 100 predictions per day and at the end of the day he will delete the wrong predictions, and so on. If he continues to do so for a month, then most of the readings will be 99% correct.
You will need to track the channel on a daily basis, which is difficult. It would be easier than that if he used third-party services such as the forum, since every modification is viewed.