Wedding Photojournalists/Documentary Style Photographers
Many photographers describe their style as photojournalism and many brides ask for photojournalistic style photos, but the term itself means different things to different people. If you're interested in this style of photographer, or if a photographer you're interested in says that they shoot in this style, it's a good idea see or show actual photos to make sure you're both talking about the same thing. (Of course it's a good idea to see actual photos no matter what they style...)
Strictly speaking, a wedding photojournalist that shoots only photojournalistic style photos will not "set up" any photos and will not do any posed photos. They'll simply arrive at the start of your wedding day (usually at your house when you're getting ready) and follow and photograph all the events of the day as they occur, right up until you make your exit from the reception. Think of them as a newspaper photographer standing back and shooting the news as it happens, regardless of what happens or doesn't happen. The newspaper photographer is not a part of the news, they simply record it.
You can get some great photos in this style, and the advantage is that they will absolutely all be spontaneous. Of course, the disadvantage is also that you won't have any posed or setup shots, which some family members tend to want. Wedding photojournalists are essentially the antithesis of traditional wedding photographers.