It wouldn't render it null and void, the transfer would still happen. By the time anything was done about any tapping up it would have been a long time down the road and far too late to say actually no he's still a Palace player. Chelsea would get a transfer ban as happened the last time they...
Let’s not paint it like he’s doing this out of the goodness of his heart for poor Palace. He’s signed a new deal on a no doubt ridiculous amount of money. He’ll be your new Zaha, ridiculous money, wants out in two years but no one will be willing to pay that weekly wage for him.
If it was...