Why exactly is it bad etiquette to ask to see a losing showdown hand?

[bav]

During the Caesars noon tourney yesterday a rules question arose, which then lead to further random discussion amongst the dealers and floors later on. The rules question that came up in the tourney was whether someone could conceed the hand after going all-in. I said no. Floor says "sure, he can always fold if he wants to". In this case we had QQ vs 66 on a Qxx board so 66 needed runner runner 6's to win so that particular ruling really didn't matter. But that's not the interesting and related what-if scenario.

During the break people are just yammering about this rules question and others when a dealer says the following came up. Three people are all in. Two guys have AK. Third guy on the river mucks his cards face down, so the AK's are going to split. One of the two AK guys invokes IWTSTH. Turns out that hand is the winner. Now what?

I claim the AK idiot who invoked IWTSTH gets 0, and the other two split the pot. Basically the AK IWTSTH's share goes to the guy who mucked the winner, while the other AK is not punished. This was not universally agreed upon by the dealers and floor people milling around. Several wanted to give it all to the guy who mucked the winner.