Situation came up the other day in a game I was watching.
A Blood Angel player moved a Thunderhawk gunship toward an objective near the other player's lines (Other player was Eldar). The Eldar player announced he would snap fire with a unit of Exarchs, and fired all 4 stands and, perhaps due to particularly fervent prayers to the Machine God, the gunship survived. As it continued on its way to the target, he then declared that a unit of Dark Reapers would open fire on it, and shot it out of the sky.
Our question was, should the Eldar player have had to declare that both units were firing at the gunship before he rolled the dice? In many wargames that is how it is done, but we weren't sure if that is the case here. (and assuming he rolled for the Exarchs first, and he shot down the gunship, the Dark Reapers shots would have been wasted.)
Next question - it says Command units who are in close combat cannot shoot, and command units who Snap fire may not later move. Should we infer from that that command units that move may not later in the turn Snap Fire - or, because it specifically says one and not the other, should they be allowed to do so?
That one came up in a game of Space Marines vs Orks, where a bunch of Nobz (like 10 stands worth) rushed across the battlefield in Battlewagons, dismounted and got into a building, and then the question was could they then Snap Fire.
We ruled that they could not, but we were looking for an "official" answer

Jake