Who are we concerned about here? OAI/Ant? The Chinese Labs? Cohere? So far the extent of the risk comes from a) OAI/Ant's models hacking when being asked to hack in poorly secured sandboxes, b) China opensourcing models that increasingly can contribute to nefarious use.
a) doesn't require a 3rd party auditor, O/A need to stop using such weak sandboxes when running such high-risk tasks. b) is a discussion with China, and again is not going to be fixed with a 3rd party auditor.
The 3rd party auditor is a great means of power-projection because you can now arbitrarily raise a barrier to entry by shutting down lower-resourced players, while simultaneously providing zero fixes to the problems at hand, but at least you make people feel good.