The "You have the Num Lock key on" warning is silly on a desktop machine, since the difference between number keys and arrow keys is visible even in password-entry mode, so the user will figure it out right away.

I assume the warning is there for people on laptops, where having Num Lock on would cause letter keys to turn into numbers, which would be a problem. But if so, then it should only be shown on laptops. And if we can't reliably tell that the user is on a laptop, then it would be better to just drop the warning entirely, because it will more or less always be shown on desktop machines, and so eventually the user will completely stop noticing it, and then one day it says "You have the Caps & Num Lock keys on" instead they won't even realize it.

(Alternate possibility: only show the warning after the user types a KP_whatever key.)