Why would we want people who haven't purchased from us to leave a review?
Example: An interested party comes to your store or inquires about a product.
scenario1 : you treat him like ####, he/she doesn't buy and leaves you a one star on google
scenario2: you show him the products and explain everything nicely, even though he/she hasn't bought yet, they leave you a 5 star
I'd say it shows in your postings on here that you don't like those situations. You want to be in control.