Assuming a merchant accept Bitcoin,
You as a shopper, place an order, and that merchant did not deliver, or sent to the wrong address, or sent a fake product.
You can not reverse the payment, you can get your bitcoins back, and the only thing you can do it leave a negative feedback.
Of course, there are many other scenarios, like phishing websites, fake websites, selective scams, and so on
What are your thoughts and ideas to prevent these scams.
I think this problem has only one solution of the improvement of the product. Because if the shopper send you the product and you didn't like or found problem then surely he will get negative response but he will remain in the market forever so he needed to improve his service and product so that everyone will satisfy with his service otherwise giving the negative trust is only a type of review which is not a solution at all .