The Kreo Boxes should have tape on them, so people would need to be breaking that open first to pinch stuff from inside (it'd be easy to peel open that tape though, which might explain why some BigWs are adding more of their own).
As with any boxed figures, always check the tape on all edges first. (I always do)

Kmart Sunnybank has 6 Ultimate Optimus primes left now.
Might have to grab one of those WFC 3-packs tomorrow before they disappear.