Oh, it's silly, all right -- not the question, but the whole TSA policy on it.
Ever since the "shoe carnival" policy started, I had made it a point when traveling with kids to have all of our shoes off and placed in our carryons when we entered the security line, so as not to have to deal with taking them off and putting them back on; just one less thing to deal with. About 8 months ago, we had done this per our usual routine, when a TSO looked at my toddler's feet and asked,
TSO: Where are her shoes?
Me: In the carryon bag.
TSO: Well, you can't do that. You'll have to get them out and put them through the scanner in a separate bin.
Me: I'd be happy to, but the carryon bag is on your side of the scanner.
TSO: Well, I'll let it pass this time, but you can't do that -- we have to separately scan her shoes. ... Wait, where are your shoes?
Me: Same carryon bag, also on your side.
TSO: <sighing> Ma'am, you really can't do that; we are required to scan your shoes separately. In the future, keep them with you and put them in a separate bin.
Me: What about the other pairs?
TSO: What other pairs?
Me: The three spare pairs of shoes that are also in that carryon.
TSO: No, we don't need to separately scan those, just the ones that you are wearing through the checkpoint.
Me: O-k-a-a-y. (searching her face for traces of irony and finding none.)
Really, is that not the most ridiculous thing that you've ever heard? What on earth would stop you from switching shoes once you got airside?