Most legal academics at most law schools have never submitted research proposals to an IRB. Most, I would guess, have no idea that their research probably falls within the asserted jurisdiction of the IRB on their campus.
If this benign (?) neglect disappears over the next few years -- as I think it will at many universities -- what will be the effects on practices in law schools, and what will be the effects on IRB practices? I have a prediction on the second question.
Based on other interactions between the university administration and the law faculty, I'm betting on some healthy turmoil. When the pension fund administrators at the university make claims and suggestions about personal and university investments, the law faculty start talking about securities fraud. When the university administration wants to "manage" the message coming from the college radio station, the First Amendment mavens at the law school get lots of air time.
The point is that law faculties, as a whole, have a reputation on many campuses for pushing back against assertions of administrative authority. They are feisty, even contentious. Other groups of faculty might prove just as feisty, but the law faculty neutralize one favored administrative technique -- claims about the law -- that work as debate-stoppers when it comes to other faculty groups.
I think this dynamic will hold true to form when law faculty start interacting with IRBs in larger numbers. When an IRB makes an overly broad assertion of power, based on its reading of the regulations, a lawyer is more likely than a biologist or a sociologist to reject the current way of doing business and propose something different. If, as Jack Katz mentioned in his recent post, an IRB sees its mission as preventing research that could provoke some legal claim against the university, a legal researcher will be pretty vocal in pointing out the weaknesses of such a civil claim. And what does prevention of long-shot civil claims have to do with the Belmont principles?
If you chaired an IRB, wouldn't you quietly hope that legal academics remain in a gray area of possible non-compliance, just for the peace and quiet?