I remember reading this rule was argued or changed because of information: if you're sure your opponent won't call a bet anyways, check and force him to show his cards even when you've got the nuts. I can't find any proof though, maybe I just dreamed it.
This is how I feel about the rule that prohibits checking back the nuts on the end. (It also prohibits merely calling, IIRC. I believe the exact rule is that if you have the nuts, you must bet or raise if a call or check would close the action.)
I've never done it, but on the rare occasion, I could see a case where you just want to see your opponent's hand, and it's worth sacrificing the last bet to do it. it should be your prerogative to do so.
Sure, this could also be used for soft-play. But if people are soft-playing or colluding, banning checking down the nuts (a) doesn't stop the soft-player from betting the minimum, (b) doesn't stop a player from folding the nuts to dump chips, and (c) doesn't prevent or discourage a wide variety of other colluding behavior and soft-play.
But it does punish an honest player for checking down for information. It punishes a novice player for making a silly mistake. It punishes a weary-eyed player for misreading his hand.
And my biggest objection: It compels a betting action that should be voluntary. Poker is a game of making your own choices and using your own chips to carry them out. This rule takes choice from the player, and all in the name of preventing a thin chance of improper play that it doesn't actually prevent.