Recognize Intel only apps on PowerPC machines

From Mac OS X Hints, it seems that Apple has implemented a method so as you can easily Recognize Intel only apps on PowerPC machines. It seems that the OS draws a Cancelled icon (Circle with a cross through it) over the top of the icon of any application you can't run on your system. From reading the comments, it's reported that using OS X on an Intel machine will also do the same thing for Classic applications.