Thanks to those who've responded, and apologies to Richard Noble and Richard Moore for my mistake with the surname. That's what can happen when you write an email in a hurry. I only did so (1) because I had a bus to catch, and have been gone from my desk since; and (2) out of a concern that my concern would get no further attention if I didn't. In the event, instead of keeping things on track, I contributed to diverting the discussion. I doubt that any of our readers is unaware that attending to quality control issues, whether in the NACO database, WorldCat, or elsewhere, is costly, sometimes prohibitively so.
What I really wanted is to allow NACO contributors who would attend to disambiguation to do so wherever appropriate, and not be prohibited by what appears to be a restriction to a conflict that occurs between NACO records. I'd like our instructions to permit resolution of a conflict whether among NACO records or elsewhere (such as WorldCat). I didn't intend to have a requirement imposed on all NACO participants, and I have no expectation that such a practice would be widely adopted. I'd guess that only a handful of people would actually do such work. But please, even if just a few people are concerned to resolve such conflicts, let's make an adjustment so that the instructions don't prohibit them from doing so.
Some respondents appeared to indicate a sympathy with this idea, even if they themselves would not do the work. Would those responsible for NACO policy and practice kindly consider it further!
Sincerely - Ian
Cataloging and Metadata Services Librarian
George Mason University