Another suggestion I had from another player would be to also add
an option to show your computer time (yes, the clock) on screen.
I suppose the rationale is that if you are playing fullscreen, you don't see your own PC clock, so you may risk to be late for sleeping, going office or school...
I don't know if it would be worth the time to code it or the use of a new cvar (cg_drawClock 1 for 24h mode, cg_drawClock 2 for 12h mode? Vice versa?)... however I write it down here, just in case someone may be interested into trying to code it.
In the meanwhile, I can just suggest people to take a look to their wristwatch or to their phone by now and then, between matches!