So, I guess I should have just done some searching before I posted. I guess my information shows my age.
It seems the issue in question is called vertical price fixing (between a manufacturer and its retailers) by some and it usually applies to either maximum or minimum retail prices. The US ruling that I remembered was from 1968 and it said vpf was 'per se' or automatically illegal. However, in 1997 the US Supreme court ruled that it was permissible to set maximum prices and that all such actions were not per se illegal. Then even more recently, in 2008, the US Supreme court accepted the use of minimum retail prices.
So, it does appear that my original memory is correct, just outdated. It now seems that McMillian can set a minimum price.
Sources:
http://blogs.wsj.com/law/2008/08/18/...w/tab/article/
http://gbr.pepperdine.edu/092/rpm.html
http://edition.cnn.com/US/9711/04/sc...ust/index.html
and of course:
http://en.wikipedia.org/wiki/Price_fixing where a reference to the 2008 Supreme court decision got me to look for the other stuff.