I know it doesn't count, but you can delete your predictions or entries after the contest, just like what I'm doing. I delete my prediction post because I think it might make my profile look low-quality poster, in case my signature campaign ends I can apply to other campaign. That way, if I apply to an open signature campaign, I’ll have higher chance of being accepted.
I'm also not really a fan of football. My predictions are just guesses. We have nothing to lose by joining those contest since participating is risk-free like the contest sponsored by bc.game.
It is possible that even subscription campaign managers may encourage participation in at least the official prediction contests from the various bookmakers on the forum. After all, prediction contests are an integral part of the advertising campaign of betting industry representatives, and managers of subscription campaigns are interested in promoting the product of their current and potential clients. So in idea there is nothing wrong in the fact that the history of posts contains posts with predictions for contests.