Well unfortunately, I don't think it can be fixed, since we alerady had anti-cheats on. It means we just have to hope ppl won't start abusing it and leaking it everywhere, else then we'll have to remove the entire arcade or just disable the highscore system altogether
And getting it fixed by the arcade mod author is not an option, because it has been discontinued it seems
Oh well at least it's nothing compared to the old forum RPG which was incredibly easy to exploit