For what it's worth, I kind of like the idea of dividing the spotter/sniper AI logic into three different categories of realism (instead of just two that Meridian was willing to consider):
1) the spotter has to be able to see the shooter in order to be able to spot it and direct snipers at the unit. Somewhat equivalent to yelling, "hey I was shot by that guy over that rock, direct your fire over there!".
2) the spotter cannot spot if it's instantly killed or knocked unconscious (the suggestion above). If you only score a non-fatal hit, somewhat equivalent to yelling "hey I was shot to my side from the direction of that big rock, direct your fire over there!"
3) the current spotter/sniper logic, which has no limitations whatsoever.
Of course, seeking equivalences and realism does not actually work if the mod uses "spotter" integer greater than 1, because in that case the hits will be remembered and the location is magically known a number of turns since the hit occurred (and the unit has likely already moved away). Also even with spotter=1 the unit might have moved (usually only a little bit) after shooting. So perhaps trying to achieve or improve realism might be a moot point.