I'm getting bogged down in the wording and phrasing of Immunity (total). States and Traits and Ammunition getting confusing, especially non-lethal Ammunition. 1: Can a trooper with Immunity (total) be 'targeted' by forward observe? Would it be a face-to-face? (it doesn't cause a saving roll, but does it activate immunity (total) due to the requirement - 'The Trooper is affected by the State indicated in their Immunity.') - I guess the question is more, 'does (total) mean (any of the states), or something else'? 2: Smoke ammunition affecting a trooper with Immunity (total)? (My guess is immunity (total) isn't triggered due to smoke not counting towards its activation requirements(?) - it doesn't involve a saving roll and doesn't cause any states)
For 1. You can target a trooper with Immunity Total with anything that is legal to cause a F2F, this includes flash pulse for example, because Immunity doesn't kick in until they would have to make a save or be affected by the state. But the Immune trooper will ignore the targeted effect of the Forward Observe For 2. Smoke doesn't affect the enemy directly so it's still a Zero Vis Zone for them
1: Immunity (Total) has the requirement to be affected by an attack it can be used against, so because those requirements need to be fulfilled before you use the skill you'll have to make the Face to Face roll first and then activate Immunity (unless a secondary skill or effect causes the roll not to be face to face, e.g. Berserk). Immunity (Total) confers immunity to game states caused by weapons and Forward Observer has such a trait, and won't lose W or STR from attacks of non-lethal weapons, so a Immunity (Total) unit will be immune to the effects of Forward Observer. Forward Observer is not a Comms Attack. 2: Smoke does not cause states or damage to affected troopers so Immunity (Total) can't be used. Smoke's LOF blocking effect doesn't directly affect anyone, either.
