I understand what you're saying, but that's not how it works. A last second snipe bid that is not the highest bid will not win an auction. It is never registered as the highest bid because it is not the highest bid. If someone has a higher proxy bid, the system knows what amount needs to be met to beat it. I have never heard of someone losing an auction if their high bid wasn't beaten, and I think ebay would have some serious 'splainin to do if that happened.
