If they gave back the tokens to losing bidders, then the auctions would be open to abuse. Just think if a token buyer with say, 400 tokens in the bank, he could see a rival that may have a limited amount of tokens, bidding for a player they really needed. The token buyer could deliberately keep bidding against his rival, knowing that their stock of tokens would be falling (as well as their cash). The bidding could go on for 50+ rounds. Then suddenly, the token buyer would pull out of the bidding and get his tokens back, while his rival, although getting the player, would have spent a significant number of tokens that they could ill afford, plus would probably have paid well over the player's worth. That's why I think its best the way it is.