Copyright: Anything is Fair Game? No.

I am being annoyed at the moment and would like friends to weigh in.  Copyright really matters.  I have given lectures about copyright infringement at fiber festival booths ("Why are you selling a copy of those Morehouse animal scarves???") and elsewhere.  I have alienated customers at the studio because I refuse to knock off a pattern from someone's copyrighted design.  But -- there is something really outrageous about a person taking an age-old design, something passed from mother to daughter, etc., and altering a row in it and claiming copyright.  Once upon a time, all of us of a certain age made slippers.  They were all alike, and they were mostly made from two strands of worsted-weight wool (then, it was Red Heart wool or Spinnerin or maybe Brunswick, which was better quality than the cheap acrylic now sold at the big box stores...and Brunswick even had matching fabric, so I likely wouldn't have made slippers out of it).  Anyway:  you cast on maybe 30 stitches, worked a three-part foot with slip-stitch dividers between the sections, then switched to ribbing to the end, pulled the end stitches together, sewed it all up and, voila, a slipper.  Well.  My wonderful Judy Champagne offered to teach one of our new "Hit'N Run" mini-courses and make these slippers.........so we Google for them and find Aunt Maggie's slippers -- under copyright????   What the person did was to move the ribbed section about three rows further along.  Nothing else changed.  It is my understanding that a design has to be substantially your own -- this is NOT substantially different from any of the thousands of pairs of slippers knitted by millions of people in the 1940s into the 1960s.  So I call it a false copyright claim, and I am prepared to use it in my class without attribution.  I wonder if people really think that you can just say you have "adapted" an old design and slap copyright onto it after having done something this minor to it?  Really infuriating.     svb