I'd read some bollocks on here over the years but that takes the biscuit. Unless there is something written into a player's contract (minimum release clause or similar), the club that holds the player's registration can decide whatever figure they like is required to buy him. This is the case until they enter the last 6 months of their contract.
The posturing is either trying to keep the player from asking to leave or bargaining for the highest price possible. If a club genuinely thought they could go to court to force a club to sell them a player for a lower price, the likes of Real Madrid would have done this years ago.
I'd love to extrapolate this out to other walks of life. I could knock on someone's door and offer them market value for their house, then take them to court to force them to sell it to me! Doesn't matter if it wasn't on sale, I offered 'fair value' and they're obliged to accept.