Yes, when they discovered it. We don't know for how long they have actually been compromised. Also, imagine if it happens again and is not discovered.

Seems like it's just your imagination: http://www.loopinsight.com/2013/07/21/apple-comments-on-deve...

That's why I started the original post with "Imagine..." :)

(Plus, a single PR release about one incident doesn't exclude the possibility of other (known or unknown) incidents taking place)