I'm always wondering why artillery in all it's forms isn't allowed to shoot blindly at hex fields (like cities or airstrips).
You always have to risk a unit for scouting first.
In WWII, and in other war games, that was referred to as "opportunity fire," as opposed to direct fire.
I imagine that could be put into PzC, but you wouldn't know if you were successful until you actually moved up and spotted a unit at strength 7, instead of strength 10. They couldn't give you those results upon the actual firing, because that would give you spotting advantages.
Hmm I remember this ability in the Civil War General series. But in games with moral, it is unavoidable you would get SOME spotting advantages. For example, if your bombard is the last hit to break the moral of the unit, you may glimps that hidden unit turn into a route as it runs up/down roads to another hex.
I think it was People's General that had a kind of counter-battery fire option. If artillery fired in support they were shown as an icon but details were missing. PG2 showed an artillery piece completely once it fired during a turn. PzC hides them as soon as they fire if they are out of normal spotting range (in FoW). Something like PeG seems good to me - allow counter-battery fire but not with full details.
As for blind fire, I don't see any reason that any information about its success should be available to the firing player until he can get a spotter in range. If he wants to fire on an unseen target in range, I think that would be a good idea with reduced effectiveness (no spotter) and no guarantee that anything is even there until a spotter can arrive.