Another "divining rod" to consider: ask about insurance. If this little venture is a genuine business instead of a hobby, it would have to account for the possibility that there is a substantial risk for injury for the customers. A credible instructor/school would likely to be insured up the wazoo to avoid losing the farm in the event that somebody stubs their toe etc. And the insurer would ask a lot of very pointed questions, and require documentation, before signing on. For better or worse, this is the world we live in.