How do you know it would? Do you know the financial incentives for clubs moving up?
All I'm saying is that the Diamonds Promotion aren't going to say at the start of the season "we don't want to get promoted," as that's almost saying "if we reach the play-offs, don't bother turning up, because we are deliberately going to lose." Which makes the season a waste of time, apart from the Cup, for the fans who are only bothered about silverware, rather than just seeing top-notch speedway every week, come win, lose or draw.
If I read it correctly, if you win the play-off, you are promoted, as that is what has been agreed, so, see my reply to The White Knight.