Everyone who works for an organization like CNN or NPR or the BBC who gets sent to war zones gets this training. It's at least a week long and might be as long as two weeks. Everyone also gets a refresher course. I'm not sure how often they get the refresher course.
One of the many problems with being independent is that they may not get this training or they may have to pay for it themselves.
I know of one organization that does not provide bullet proof vests for the local hires that they use for translators. A good one is quite expensive and necessary for one's safety.