The "serious" researcher

"...All books are written to express man's ideas and libraries are formed because other men wish to read and study those ideas. The cataloger's main business to make the collection of books and materials accessible to all who have a legitimate claim on its resources."--ALA Cataloging rules, 1949.

One of the old cataloging manuals here at the university has that quote on the very front page; a reminder of the goals of a cataloger. Considering that even in the 1950s, the department used students to do the cataloging work, its very interesting what this quote represents. The cataloger who put that in there wanted to give his workers a sense of the purpose of cataloging, not just the drudgery of filing catalog cards. "men wish to read and study": yes, that's why we're here. To serve them.

Ah, but now the tricky part comes in! The cataloger is supposed to serve "all who have a legitimate claim on its resources."
In the research I've been doing on early-20th century libraries, this idea of legitimacy comes up all the time. In 1930s statistics for one special library, the librarian only reports the statistics of "serious" researchers. He never defines what that means, of course, so I am left to speculate wildly on what that might mean. What constitutes serious research? Is an undergraduate student "serious"? In other words, does this 20-year-old have a "legitimate" claim on resources?
While I suppose that when I was 18, I was hardly worth any librarian's time, I do like to snuggle myself to sleep at night thinking that librarians are no longer like this. We no longer assign value judgments to our users' intentions or skill level. But guess what? I totally did that JUST YESTERDAY.
To set the stage: one of our reference librarians called me up, and asked me to come out to the desk. She asked me to put on my "archivist" hat. So out I come, and she shows me what she's been working on. It's a "currency" progression (currency as in whether or not something is out-of-date, not whether you can spend it), and archives of course falls to the back of the pack. Then she shows me a "reliability" progression, and archives are just one step up from gossip! I am taken aback. We discuss this for some time, and it becomes clear that all she's trying to do is help the students understand how subjective archival materials can be, especially when they are manuscripts. But what about business records! I want to shout. Anyway, I think over the problem, and we talk some more, and we decide to remove archives entirely from both of her progressions. Why? Because these students that she will talk to, because they are not as advanced as we great librarians, will be confused and will make bad value judgments on archives if we leave it in the list.
Who am I to say that all of these students are idiots? Or worse, uncaring of their ignorance? Surely they would like to learn all about archives? Or am I just superimposing my own love of archives onto them?
I don't know where I meant to be going with this, but it troubles me that while I talk about how "backwards" librarians used to be, with their notions of the serious or un-serious researcher, I myself make value judgments on our users all the time.