The contractors can be held to that standard, as part of their employment contract. It's quite the trick to get the UCMJ to apply to guys that the government isn't even PAYING, and who have to reimburse the government for per diem costs of their chow and lodging and so forth. I think the former is good and likely, the latter not good and a bit more unlikely:
That may be about to change, Brookings Institution Senior Fellow P.W. Singer notes in a Defense Tech exclusive. Five words, slipped into a Pentagon budget bill, could make all the difference. With them, "contractors 'get out of jail free' cards may have been torn to shreds," he writes. They're now subject to the Uniform Code of Military Justice, the same set of laws that governs soldiers.
In that Defensetech post, Singer explains how he believes the new law will change things for military contractors. But could it also mean that embedded reporters will now end up being subject to the same justice code? Singer writes:
The Iraq war is the first that journalists could formally embed in units, so there is not much experience with its legal side in contingency operations. The lack of any legal precedent, combined with the new law, could mean that an overly aggressive interpretation might now also include journalists who have embedded.
Given that journalists are not armed, not contracted (so not paid directly or indirectly from public monies) and most important, not there to serve the mission objectives, this would probably be too extensive an interpretation. It would also likely mean less embeds. But given the current lack of satisfaction with the embed program in the media, any effect here may be a tempest in a tea pot. As of Fall 2006, there were only nine embedded reporters in all of Iraq. Of the nine, four were from military media (three from Stars and Stripes, one from Armed Forces Network), two not even with US units (one Polish radio reporter with Polish troops, one Italian reporter with Italian troops), and one was an American writing a book. Moreover, we should remember that embeds already make a rights tradeoff when they agree to the military's reporting rules. That is, they have already given up some of their 1st Amendment protections (something at the heart of their professional ethic) in exchange for access, so agreeing to potentially fall under UCMJ when deployed may not be a deal breaker.
The ultimate point is that the change gives the military and the civilians courts a new tool to use in better managing and overseeing contractors, but leaves it to the Pentagon and DOJ to decide when and where to use it. Given their recent track record on legal issues in the context of Iraq and the war on terror, many won't be that reassured.