I would suggest it would be more un-gentlemanly to demand your deposit be returned, than to not return it.
It undermines the whole deposit process, and everything it stands for.
If that is the case, then there will be no holds, no deposits, nothing is sold or unavailable until the sale is final, and that is NOT how it is meant to be.
If Yellow66 is correct, the world has just become a slightly sadder place....