They could also insure the vetted companies' clients and shareholders against this kind of failure.
The premiums would be out of reach of most small businesses, members. Just think of how much such an organisation would have had to pay out from the failures which have happened this year alone. Its in the millions.
The idea being that the vetting process itself would protect the insurer against having to pay out, and more importantly, keep the company on the up-and-up so that it does not fail in this way.