Here's a copy/paste from an informative post in the "Copyright Matters" group over at Ravelry, in response to my post about the McCall's copyright issue:
"The McCalls of today is not the same company that published the knitting patterns of the 70’s. McCalls sewing sold their knitting magazine division to another company. I happen to know that company destroyed all the patterns they had in the archives and have no interest whatsoever in the copyrights to those patterns. So, no, McCalls isn’t going to come after anyone about that cuz they don’t own those copyrights any more. They are/were owned by a Japanese company. The same company that has given me permission to post pdf’s of those old patterns on the internet if I so desire.
So, No. McCalls isn’t coming after anyone for sharing a xeroxed copy of one of those old patterns."