The main question is, what if you have evidence that is quite strong but doesn't amount to proof?
If you have any evidence whatsoever then the first thing you should do is tell the arbiter. The arbiter's job is then to judge that evidence and then see if there is any more evidence to support that claim. That includes not just what has happened in the past but also what happens in the future.
As an arbiter who has been in that position I can tell you that the most stupid thing you can do is broadcast to the world. That guarantees that the people tasked to find more supporting evidence will fail.
Obviously when such an accusation is made to the arbiter there are two possible outcomes:
- Cheating is proven and the player faces sanctions usually including a ban
- No cheating is proven. In this case the accused is innocent and should have no stigma attached to them.
Let's look briefly at the Niemann- Carlsen case.
- Strong players have analysed the game and concluded that Carlsen played badly. It looks very much like an older insecure player trying to deflect from their blunders by a false accusation of cheating against an improving younger player.
- IM Ken Regan has run Niemann's games through his cheat detection program and come to the same conclusion that Carlsen played badly and Niemann played well but nothing exceptional.
Regan is used regularly by them in serious cases. He has analysed Niemann's games and published the results. He has appeared in a number of interesting YouTube videos discussing these. Here is an example.
Ben Finegold, who proposes that all evidence (no matter how flimsy) should be discussed in public. He says that it is possible to regard an accusation of cheating as a compliment
GM Ben Finegold is more of an entertainer than serious chess player these days. His current FIDE rating is 2400. He makes money by producing hundreds of YouTube videos and getting revenue on the number of clicks. Saying dumb but controversial things is a good way of driving that.
Carlsen, at a much higher level, is currently making a similar transition, this time from professional chess player to businessman. He has strong business links with Chess24.com and increasing revenue for them by saying outrageous things is good for him on a business level.
What would the consequences of this proposal be?
Putting legal considerations to one side, the first and most important consequence would be that a possible cheater would be alerted and no more evidence would be gained. The only evidence would be historic which would likely already have been analysed. The second consequence would be to bring the game of chess itself into disrepute as a safe haven for scuttlebutt, innuendo and libel.