Probably not the best time to announce a kickstarter, regardless of whether or not anyone on AI War 2 would be working on it.
It's absolutely the time to announce it -- waiting until after the fact to mention it is much much worse. Given we have full intent of this (though it won't even be under Arcen's account on kickstarter -- this is separate folks working on it, etc), it's much better if we let people have all the information now.
I imagine that your argument is probably that people may avoid backing one of them for fear we're doing something shady? There might be other reasons, but that's my top one, anyway. In those cases, I'd rather have people not back us based on having info in advance instead of back us and find out an unpleasant (to them) surprise.
I've talked about this a fair bit on the later updates of the first AI War 2 kickstarter -- and while I'm not intending to make it some sort of in-your-face "look at this other thing!" issue, I do want to be clear in terms of "hey, full disclosure, here's what's up and why it's not what some other dirtbag developers have done."
That's the rationale, anyway.