A lot of premium resource authors are adding people to the buyer list in order to get good reviews out of them I have 2 ideas how to handle this 1. Simply disable buyers from the buyer list from reviewing the content. 2. If the buyer got the product for free ( aka added to the buyer list ), create a little warning in his review, saying "Received product for free". Now I know in some weird cases real buyers are added to the buyer list, that is extremely uncommon, and even then, This suggestion doesn't hurt them in any way shape or form.
reviews are pretty useless anyways. if you want to know if a resource is good, you look at the discussion section. the reviews are full with ppl either saving nothing and spamming something to reach the char limit or stupid ppl reporting bugs (which are often caused by missconfiguration). there are also many resource where bad reviews just disappear after a while (most often because they got threatened by the author). basically, its like every review section ever.
Not even sure why reviews are in place when people can actually discuss it in the Discussion section, not to mention that's where all the mythbusting takes place.
Here is one. Stop caring about the reviews. Alot just press the download button to 1 star with BS or someone can't configure it correctly or follow instructions. People do it because they know you will respond.