Keyboard shortcuts

I know that this doesn't really address your concerns, but it might be easier to edit the keyboard map to disable the keys you do not want to use.

There are three promising leads on this page:
unix.stackexchange.com/questions/74151/f...-disable-prntscr-key

The relevant idea here is probably:

One way to do that is to comment it out in your X keycodes file (the one corresponding to your keyboard - linux uses /usr/share/X11/xkb/keycodes/evdev). Key code is <PRSC>, just comment it out (add // in front of it) e.g. replacing

<PRSC> = 107;
with

// <PRSC> = 107;
completely disables PrntScr.