Can you apply this same approach (i.e. full refund to an unsatisfied customer) and still be successful as a consultant/freelance? I feel like the stakes are higher because the client could rack up a huge bill then play the “unsatisfied” card leaving you high and dry for your time.
If the service is writing code, I won't give them the work if they end up wanting a refund. If the service is something monthly, I'd only offer a guarantee on the first month. So I'd say it would still definitely work for freelancers/consultants. Jonathan Stark has a lot of material about this subject that covers more of the nuances.