Vintage patterns: my guilty conscience eased?

I'm taking some pretty intensive Intellectual Property classes this summer, so I end up coming across some issues that I can't help but immediately link with the number one thing that takes up space in my brain - knitting. This morning, we discussed the mechanics of the term of copyright - in other words, how long things end up getting copyright protection. A lot of stuff created after 1923 still has copyright in the US - all those classic movies, songs and most relevantly, knitting patterns - as long as the copyright existed as of 1978.

Recently, I came across a link to Vintage Knitting Patterns at glamarama.net. Glamarama has posted a number of vintage knitting patterns that she believes have fallen into the public domain. She's probably right, and even if she's not, I think she's covering her bases by telling any potential copyright owners to let her know if they want her to take them down. However, it seems like there might be some sites out there (do some googling) that might not be so concerned with infringing any copyright that might be attached to these vintage patterns.

But here's the thing - I'm not sure how I feel about those sites posting patterns where it's possible that there's still a copyright owner who wants to control the reproduction of the pattern. My first instinct is that it's wrong - the copyright owner gets to say what goes and what doesn't, right? But a lot of the time, these patterns are not commercially available, the companies that originally owned the copyright have often gone out of business and the writer of the pattern might not even be alive. Is there any harm in making these patterns available to the public so that they can be used as they were intended? Personally, I think the issue comes down to the fact that this is a user-enforced system. If the owner hasn't taken any steps to enforce his or her copyright, then the "infringement" can continue unnoticed and all the knitters out there get access to patterns that we wouldn't otherwise be able to find. Anyone else feel any differently? There's got to be someone. If so, please leave it in the comments - I love comments!

In the meantime, I'm going to add the Mohair Shrug from glamarama.net to my "to knit" list. (.pdf pattern here)