I'm less certian of this one, but I suspect that the answer may be a
reasonable yes here. My reasoning being that in order to receive
"WillEnterBackground" the app must be in the foreground. And I think
Android's "killer" targets backgrounded apps not the one foreground app
(for the obvious user experience reasons).
But I've also seen mentioned that the best cource of action for Android
apps is to assume that termination might be immenent at any moment and
program defensively to that assumption. Which means commit to storage
any user data as soon as the app. receives that data from the user.