I vaguely remember this being a technique for getting past doors in the Splinter Cell stealth games (2002).

I did something like that but with a laser pointer and its speckled pattern - https://www.anfractuosity.com/projects/fun-with-speckle-patt...

That (plus wear, probably more wear) is why some touch screen keypads randomize the numbers every time.

Unfortunately those keypads aren't ADA compliant, since blind people can't use them.

Wouldn't any touchscreen fall into that category? One with changing buttons to press?

Mitigation, such as speaking the touched button for confirmation would be troublesome.

There could be an option to set it to 'standard mode' for disabled customers.

Basically all attempts at increasing security will make it more difficult for somebody. For example, 4+ pin digits (bad memory), fingerprints (no fingers), etc, etc.

The question is, is it worth having reduced security for the very few edge cases?

The Splinter Cell games were way before their time!

Interesting to see that it works in practice.

You can fool the system by heating one of your hands under your arm and then cycling between both sets of fingers at random. The different initial temperature condition will break the assumption that each button press started with the same heat flux.

Tom Clancy loved figuring out military tech. His books are full of stuff like that.