Yes, it is too simple. If a vendor wants to pose as a buyer and post fakes reviews if there is no cost to the transaction itself then there is no cost for the v

Yes, it is too simple. If a vendor wants to pose as a buyer and post fakes reviews if there is no cost to the transaction itself then there is no cost for the vendor to post a fake review. In Silk Road the cost of producing fake reviews was the commission cost of the sale.