Money back guarantees are better for the consumers and better for the producers. There's still psychology involved at $15, and more than anything it's to mitig

Money back guarantees are better for the consumers and better for the producers. There's still psychology involved at $15, and more than anything it's to mitigate loss aversion. If I spend $15 and the product sucks, I loose a lot more than $15 worth of happiness. Its fine if these guys don't like the advice. And, yes, Starbucks does offer money back guarantees, usually at the rate of "this one's free and so is the next one."