If it was a 'feature' then why did they remove it in SL? (And no, I wouldn't want this 'feature'...) But I agree that there must be some way to remove this behavior by using the 'defaults' command (or manually editing plist files.) I'd try to find it, but I don't have a Leopard machine to reproduce the issue on.

It hasn't been removed from Snow Leopard. Maybe Spotlight doesn't participate in it anymore, but for normal find dialogs, the feature is definitely still there. And I do agree with you btw that it is annoying and very rarely useful.