What airports have installed the "Carry-On Luggage" Sizers (for lack of a better term) at their x-ray scanners? Some of you have first hand experience of this, because if the luggage doesn't fit, you get the privelage of checking your baggage.(This may be in a previous post, if it has I know somebody will let me know the web address).

The only one I've encountered (so far) was in Sioux Falls, South Dakota.