Invulnerable Saves

Source: 3rd-A-Palooza (3.5) Rulebook v1.4, p. 22

A model may only elect to use its Invulnerable Save each time it is allocated a wound under the majority rules given above.

Designer's note: This last obscure reference is to prevent individual models with storm shields, rune armour, et al, taking a disproportionate amount of the damage during close combat, claiming they can break the majority rules or other weirdness.