Acting Under Fire is just so abstract, that there isn't a great phrase to universally describe when it happens (Acting Under Fire isn't one), but that doesn't mean that it isn't a consistent fictional occurrence.
Well, isn't that because it's abstracted? "Being under fire" is actually a phrase that
means something, (I take it to mean, "being in the line of fire of something that is actively dangerous to your body") and when we extend the move out past that meaning, the extended usage makes less sense. That's my argument with SBF too - it's fine when you use it within its natural-language meaning (although, frankly, "seize" contains "by force" in its meaning so I find it to be an onerous pleonasm) but when you extend it out past that, it becomes harmful to the game.
I would say that AW is designed such that you kinda have to know how a Move works mechanically to know when its happening - Players don't arrive with a perfect understanding of what Going Aggro means, Seizing By Force doesn't necessarily require that you're really trying to acquire anything, but it does require that your target is fighting back, for instance. Maybe the learning curve is worth it, maybe it kind of sucks.
It kinda sucks, because there's nothing
that prevented it from being written more clearly. The book is huuuge and there's basically no imaginable excuse for it not including simple, clear language like,
"Go aggro is the move you use when you're threatening someone with violence but you're not executing violence yet, and Seize is the move you use when a guy has something you want, and you're violently taking it (see how I used the definition of "seize" there) from him."My better half Elizabeth SOME PERSON wisely suggested that V likes to write examples of play about edge cases, and the Seize example is one such edge case. I think that person is right, and that's highly problematic unless you're quite familiar with Vincent's opus and you are conscious of this tendency. If you don't have that corona of knowledge, the example is misleading, and there's no example of a core case usage of Seize, to compound the problem. Familiarity with a writer's tics and bad habits should not be a prerequisite to playing a game effectively. The move is not precisely mechanically bad, but it's mounted in this surround of badly written instruction and examples that confound it.