Just found an item on Envato. Instead of item description, main text says - The next buyer of this article who can give a 5 stars rating will get a free product by mail from my portfolio here at ENVATO — Thanks for your support
And then author provides a screenshot with detailed instructions where buyer should go and what exactly he should click to leave 5 stars rating for his item.
It looks Envato contacted author, but I’m slightly disappointed about the outcome. Author simply removed these advertisements from all descriptions of this items, and… this is it. All those 100+ paid/sponsored reviews for all his 17 products are still there, which I don’t think is fair.
In other words, it means any author can promote something for free in exchange for 5 stars rating, and if someone reports it, he can remove advertisement and get away with it. So such an author gets more sales (because he offers another product as free bonus) and fake 5 star reviews, which leads other buyers to think all his products are great. And no penalty at all. I think this is a huge hole in Envato system…