I see your point. We wouldnt want pilots offering to fly for free or god forbid, pay to fly.
For things like flight tests and technical articles I can see that this would be the bread and butter for staff writers. Flying trip reports however as far as I can see, tend to be from a range of people . I wouldnt have thought that the magazines send people off on these kinds of flights just for the article would they. I stand to be corrected though.