This is the kind of cheating on tests or at games where one is never caught. It sounds odd to use the word never but I can think of two people I know who have done it.
One of them is a chap who is paid to take exams for others. He has been doing this for years. There has never been the slightest glance at him or the person he is taking the test for.
So imagine, there is John paying him to sit a sociology exam. He goes in, he takes it, he comes out, John passes and no one ever calls John into any office or questions his achievement.
Because John scores somewhere in the middle. He doesn’t come first, nor second, nor sixth. It there are 100 people taking the exam, he would score in the upper thirties. If the best grade is 98 he will score 81. He always makes sure to miss particular questions.
Another person I know plays a game online with a cheat program. Because he takes so long between moves, there is no sense he could be cheating.
Both of these cheaters have hit on a fact that is never noticed; if one stays in the middle, if one takes enough time to have formulated the play, they will never be caught.