Some reviewers are very entitled. Don't send them a review part, they start a crusade against you. I've even seen a reviewer tell his own audience he had no intentions of returning review samples, well not until he was "done" with a winky face.
The question of ethics is starting to stand out more. Most of these review sites aren't even staffed by legitimate journalist that took courses in Journalism. They are bloggers that got popular. So they don't seem to have an issue with firing a tweet off "didn't get my review sample, clearly something is wrong" as it poisons the well of what should inherently be an objective person. Clearly this person is already subjectively angry and his review may harbor that.
So who gets review samples? And some people posted here - every dick and jane that has a blog with a moderate amount of traffic? Or specialty shops that have a huge user base? And if you say specialty shops, should you not factor their inherent bias?
As someone who works in the medical field, the change to how pharmaceuticals can promote their products really affected things (for example some of my employer's bottom line). Lavish luncheons with presentations, gift baskets, free medical samples, pens+notepads (and a manager at one clinic didn't realize just how much money they were saving buy not having to buy their own pens+notepads+stationary haha). It all adds up.
To bring up the gaming industry, recent article be someone who got paid to attend a preview of Rock Band 4. Guy didn't even bother to even participate in the lavish event held on the roof top of an expensive hotel. His article? How much he doesn't like music genre games, and how everyone at the event looked retarded. Dat journalism!