I think Justin's concern illustrates my own hesitancy as well with the breadth of certain questions that we sometimes get asked as judges. And sometimes there is going to be “Those questions” that are indeed too broad to be answered without either giving advice, or even offering the
appearance of giving advice. Yes, it may very well be possible to answer some of these “theoretical questions”, provided there is some expectation that the situation is going to happen. (For example, "Can I play
Dark Betrayal targeting
Blood Baron of Vizkopa?") But, it is possible to extend that a bit too far and cross into some rather dangerous territory.
In such case, I much rather prefer to get the player to walk me through the scenario and see if I can/can't confirm their understanding of events. At least then I know precisely what the player is asking, without providing more than confirmation of the scenario and its legality. Even that can be tricky, since while you do want to offer an explanation if they are confused, you don't want to overexplain.