So.. Can the Koala go for the Legates? I want yes on this but isn't this the same as when you move two+ units in a Fireteam or a G:Servant? If the Servant moves in and triggers an ARO and you don't take it it's wasted even when the unit who has the Servant moves in?
Sorry but this seemed to have sparked the entire discussion. While that is indeed how Disposable is handled for i.e. a Panzerfaust, it is not how a Deployable weapon is handled. Perimeter weapons have an extra clause that handles expenditure. Nothing in it suggests that wrongfully declaring a Boost against a Target 8,1" away results in anything else than simply the Declaration turning void. For the purposes of the Expendable Trait, a Perimeter Item is spent when it detonates, it is in Disconnected state, or it is placed in Stand By Mode.
It's how Koalas are generally played. Certainly in my meta. It's worth noting that Koalas are both Deployable and Disposable(2). Disposable means: The only sane way to play this is: 1. Check whether the AROing Koala actually got a ZOC ARO, if yes go to 2, if no there was no ARO, therefore no declaration was made and the 'ARO is lost'. 2. Check whether the requirements of the declaration were met, if yes go to 3, if no the Koala is expended but there is no further effect. 3. Explosions! Perimeter items DO NOT MAKE SENSE if you try really really hard to break thm. Stop trying to play them by really really close reading and just play them sanely.
I like this, it makes sense. Just have to remember that you check 1 during resolution for any point in the order (just like BS Attack). Only problem left would be what happens to the Koala following a failure to declare - either through forgetfulness or through tunnel-visioning on a specific model.
Expend it (with no effect) or do nothing. I'd offer either option, and it'd depend on what the non-owning player wanted. Because at that point you've (inadvertently, most likely) cheated. Yes, the way I read the FAQ is that you just have to have been in ZOC at some point in the order for the ARO not to be lost. My meta plays it exactly the same way for Hacking.