Quote Originally Posted by De Montfort
The crossbow was largely useless at long range. It couldn't fire effectively in an arc which meant it was only really effective at less than 100 yards.
This is not true. There are human remains recovered from battles that have bolts sticking through the top of the skull and the front at a 45 degree angle. One woodcut from the period shoes crossbowmen firing up at a 45 degree angle, and bolts falling down vertically on the enemy's heads like rain (source and image: Strickland & Hardy, "The Great Warbow" page 283).

Crossbowmen may have preferred to fire at closer range in a flatter trajectory for maximum penetration, but it's a ballistic weapon (no such thing as a truly "flat" trajectory), and they would have been well aware of how one could gain more range with elevation. Also remember that a crossbow bolt (especially one of the larger ones) is heavier than an arrow, with less fletching to slow it down. Now think about firing that in a high arc, and letting bolts fall down near-vertically on the enemy. Sure, it's not as effective as a close range, "flat" shot, but it's going to have some effect... if the recovered bolts piercing the roof of unfortunate soldier's skulls mean anything. If you had time to reload for a second or third shot before the enemy closed on you, and plenty of bolts, then why wouldn't you try an arcing shot first?

Now, whether or not CA has implemented it that way is another story. I can see where they might restrict the range and incur friendly fire casualties if placed behind your own troops, mainly for gameplay reasons... i.e. forcing different tactics for different units.