Several years ago (I believe I was living in Atlanta at the time), someone opened a similar concept using a garage. The guy closed out his gas pumping side and started charging out the use of his bays, lifts, and tools to individuals who wanted to do their own work on their cars. He had to close after a few months because he could not afford his liability insurance, even though he made the users sign an extensive disclaimer.
I'm wondering how the maker communities discussed in the episode have dealt with the liability issue. Shop accidents are not uncommon, and even very experienced professionals saw off a fingertip from time to time. Hopefully, they have found an ironclad disclaimer document for the users to sign that provide sufficient protection. It would be worth putting the question to someone who has successfully worked to set up one of these organizations.