Well, I am pretty sure (feel free to correct me if I am wrong!) that team relocation has been blocked plenty of times in the past. This being about a sale is a little different. However, I could see the other owners blocking relocation but allowing the sale to Hansen, which would probably lead to Hansen withdrawing his offer on the Kings.
Actually, I wouldnt be surprised at all if it went that way. Then the pressure is off the BOG, technically they didnt meddle with the sale to Hansen, they just veto'd the move. That would put the ball in Hansen's court about whether or not he still wants the Kings, or would rather pursue another franchise to bring to Seattle (and I think we all know which way he'd go on that one!).