Ethics of Giving Your Product Away for a Testimonial

I was watching TV this weekend and happened to see a commercial for The Total Transformation Program, (https://www.totalparenting.com), which helps parents transform their child's behavior from that of rage, anger obnoxiousness to one of a cool, calm, and respectful child.  I don't have any idea if the program truly works and is effective.

What I found interesting about the commercial was the guarantee.  If the buyer completes a survey within 90 days of paying for the program, (I think you have to complete 9 surveys, one for each lesson, and each survey takes about 30 minutes), the company will refund the full purchase price of the program, excluding shipping and handling.  The total cost of the program appears to be $346 with U.S. shipping.

In a way, I think it's sheer genius to offer to refund the program fee for the testimonial.  In this case, the buyer really has to work to provide the testimonial — they're looking at 4.5 hours of work to complete the surveys, if I understand the process correctly.  The purchaser can't get away with simply saying, "It's great and it worked for my kid!" and get a refund.

For those buyers who participate, Total Transformation is getting valid testimonials from users.  And, they can evaluate the program along the way, checking the surveys to see if there is some breakdown in the system or whether certain lessons are creating problems for the buyers.

However, could this be construed as paying for testimonials?  And is that a wrong way to elicit feedback on your product or service?  I'd love to hear your opinions.  Would this work in your business?