During the last 30 years that I've covered audio, I've written for many different publications. Each one has had a different policy and philosophy on how much advertisers and advertising should influence editorial content, as well as how much interaction there should be between reviewers and manufacturers.
Some publications, such as Harry Pearson's "The Absolute Sound" of the 1980's; had a strict "no contact" rule between reviewers and manufacturers (except at CES, but even there interactions of more than five minutes was frowned upon, except when the manufacturer was picking up the tab for dinner). And while "no fraternization" did eliminate a primary source of temptation for reviewers, it also made for a more ignorant and isolated bunch of reviewers. Enforcing such a policy today, with the plethora of communication avenues available, would be impossible.
Titling wildly to the other extreme, I've heard unsubstantiated rumors about publications that tied their editorial content directly to advertising. I won't name names because none of them are still in business. But among the printed magazines and internet sites I've worked for over the years, none have ever had conversations with me about "featuring" an advertiser just because they were an advertiser. And looking over the list of advertising that supports Audiophile Review, there are a few companies I've never written a word about. Ever.
Sometimes a manufacturer or even ex-manufacturer has approached me in my capacity as editor of Audiophile Review with a technical white paper or theory piece for publication. I've run several that I felt had something new or which explained basic theory well. But a few haven't been published, primarily because I felt they were too advertorial.
For some folks only the level of separation embraced by Consumer Reports is adequate proof of a reviewer's honesty and pure intentions. But in the real world, where shades of gray far outnumber black and white, some interaction between manufacturers and reviewers is necessary, and I believe, beneficial to consumers, because the better-educated and more knowledgeable a reviewer is, the more accurate a review will be.