In Australia there's a specific Code of Ethics that journalists are supposed to work by. http://www.alliance.org.au/media_alliance_code_of_ethics/ - other countries may have similar things, but it basically sets out the role of good journalism.
You can easily argue the public interest was served by releasing the wikileaks video. The iPhone reveal is just tech industry gossip.
Also, wikileaks isn't hosted in the US and thus doesn't have to obey to American laws. They also did not steal those videos these are copies and in my IANAL opinion is completely different.
1. Powell takes the photo that he posted to Facebook, but uses the front-facing camera to do it. (Hey, field testing under real-world conditions!) 2. Seller notices this (iPhone with a front-facing camera? WTF??). 3. Seller puts two and two together ("cha-ching" noise, dollar signs roll up in their eyes, etc.). 4. Seller sticks around for a while, picks Powell's pocket at the first opportunity, and bails. 5. Seller lays low for a while to see if word gets out, thinks up a plausible story, then makes the rounds of the tech blogs. 6. Profit!
If this is what Apple believes happened, it's unlikely they'd take any action (assuming they take action at all) until after the phone is announced/released. Starting that ball rolling now would be too big a distraction from the actual launch. But after that it could get very ugly for Gizmodo very quickly.