I stopped reviewing for one publisher who had games there when they suggested I could copy-paste text they sent me if I didn't have time to do my own review... 
Hahaha, yeah, it seems some game publishers view reviewers as a source of free advertising and, as long as they send them a free review copy, that the reviewer has an obligation to write a good review.
Recently, on The Escapist game site and Youtube channel (the current home of Yahtzee) they had an issue with Sony. Sony used to send them free review copies without them even requesting them but then, after a less than glowing review, emailed them saying "We do not like the tone of your latest review so we will not be giving you access to free review copies of our products in the future."
An email which The Escapist had the journalistic integrity to immediately expose.