I think your take is likely spot on. When I counsel organizations about new policies or "rules" they want to enact (which I do on a semi-regular basis), among the questions I ask is: "what are you trying to accomplish with this policy" and "are you willing to do whatever it takes to enforce it?"
You may (or may not) be surprised by the number of executives and administrators who answer the first question with: "I don't know...someone said we should have this rule". If that is the answer, a lot more discussion needs to be had before we adopt anything. Maybe it's not necessary at all. Maybe it's covered by other things. Maybe it will make the situation worse.
...but if there is no law that would impose liability on a range owner for a patron shooting an unregistered supressor....why have the policy? Just because someday there might be such a law? really?
I also counsel businesses on things like that. In terms of "why have the policy," I think it goes beyond what the law may impose in terms of liability, since laws are notoriously poor barometers of what can create liability. Better to have at least a minimal policy, minimally enforced, than no policy. At least that is my experience.
Or, we should also be careful what we wish for. NFA owners are still a HUGE minority. A simple, no-thought-required policy is to not allow any NFA items at the range. Done. Problem solved, no need for autonomous ROs. Particularly if "we" (or VUPD in this case) don't have "satisfactory" suggestion for a policy, then an easy-to-enforce but ultimately disappointing policy could be the result.
@chipbennett
I recognize the deficiency in the analogy, but it was only that. Plus, there are other ways to confirm income without access to my 1040, including an affidavit that the number I provide is correct, or copies of 1099s/W-2s (still tax documents, but more analogous to the NFA tax stamps). Even so, I think the analogy serves its purpose.