If a rifle grenade strikes a unit which is too close to cause detonation, there is no effect at all. In real life, being struck by a 40mm grenade at close range, such that the grenade does not detonate, can cause serious injury or death from the impact alone. In the game, it doesn't even stagger a struck soldier. Indeed, the struck soldier will not even register the event as having occurred (except maybe by sound), and friendly units will not yell, "Cease fire!" as they normally do in response to friendly fire.