Welp, that's true, my bad! It seems this rule was relaxed somewhat - mentioning the stack in the rules text is still frowned upon, but there's still some cards that mention it in the rules text (and a lot more that contains the split second reminder)

Note how the waterhouse's link - https://gatherer.wizards.com/Pages/Search/Default.aspx?actio... - contains a bunch of cards that were playtested but eventually rejected (they are the black-and-white cards with just a rough sketch in place of art), presumably because of the high bar that stack-fiddling cards should meet