I have first hand experience with this (Score 1)

I can honestly say after having worked for a both a large and medium sized network in an editorial and PR capacity that this is not an uncommon practice. I have been pressured by management of the site to not give a title coverage because they would not buy advertising and the reverse has also happened. Pressure from the publishers to change a review to meet a certain score or they will pull their advertising money is not something that happens every day, but it does often enough that I am surprised it took this long for someone to be very public about it.