Carl:
In practice, too, some of the architects who are consultants to these courses do their best to attach their names to the course as well, hoping to raise their own profiles by being mistaken as the real architect for the place, or at least as a successor to the famous Old Dead Guy.
For me, the two keys to attribution are (a) who did the routing ? and (b) who built the greens ? Those are the real DNA of any course. Bunkering gets rebuilt and moved around so often on most courses that the credit becomes murky, and on many courses it's just window dressing anyway. Greens are never window dressing, every golfer interacts with each of them.
If a bunch of greens have been shifted in position or rebuilt -- as at, say, Augusta National -- then there is some scope to start assigning multiple credits, but if there are several different guys involved, usually one would just fall back to the original designers as having done the majority of them.
Personally, my preference would be for the course itself to identify the original designer, and any subsequent significant designers (which to me implies more than being a consultant). For example, if Ross did the original design in 1927, and then architect H.D. Doody made "significant changes" (whatever you take that to mean) to the course in 1998, I would prefer the course identify the designers as follows: Architects: Donald Ross, 1927; H.D. Doody, 1998. Just my preference to give credit where credit is due.
The problem with that is, who speaks for the course? For a new resort like Bandon Dunes it's an easy question, but the answer would have varied over the years at a course as good as Royal Melbourne about whether to credit Alex Russell or Mick Morcom alongside Dr. MacKenzie. In fact, the answer would still vary, depending on whom you asked there.
The other problem is that it encourages consulting architects to make changes "significant" enough to get a credit for themselves. I was talking about that with Ian Andrew a week ago; we both feel strongly that subsequent architects should NOT get credit unless the routing is overhauled or a new set of greens is built. In fact, I wouldn't feel right putting my name on the Country Club of Detroit, where we just DID change all 18 greens a couple of years ago. I think it was an improvement to the course, but I wouldn't call it "my design".
As to whether Ross deserves credit for "Ross" courses, Brad Klein did his best to identify where Ross made site visits during construction and where he didn't, but no one has paid too much attention to that research, because nearly all the Ross courses we actually talk about are ones where he did make site visits.
From my viewpoint, whether Ross did nor did not visit the site - ever - although important to know, would not be a key factor in calling a course a Ross course. During his prolific period, Ross had a team (Donald Ross & Associates - including Hatch, McGovern, Johnson [no relation to me!]), as do many "architects" today. My understanding is that in many cases Ross would lay out the routing based on a topo of the property, and maybe some other features, but leave the details to other members of the team on site. Still, originally a "Ross course."
I've done a couple of projects where the routing stayed essentially the same from one I had done before visiting the site, but it's rare that happens. Plus, do you really know whether Ross did all the routings, for projects he didn't bother to go and see? I think it's okay to credit him for those courses, since they were done by his company and we have no idea who if anyone else should get partial credit, but that's no different than all the modern signature designs where we don't really know who did what.