If you wanted to take it a step further, the touch screen could have a very narrow viewing angle, have the angle of the screen automatically or manually rotate to the users eye level, and then someone standing next to you would just see a blank screen. With random keys on top of that, someone would literally have to poke their head over your shoulder to see.

If they're going to do that, they need to do it consistently...

Most ATMs around here don't randomize the layout, but every once in a while I come across one that does, and I've found that it's actually quite difficult to use the latter. Apparently I have my PIN memorized mainly through muscle memory... when using the randomized sort I've occasionally resorted to drawing a keyboard and looking at what numbers my fingers hit! ><