Here's an interesting data point I noticed in the blog linked on the front page.
In the picture of Rod Dixon winning the 1983 NYM, he has a Saucony singlet with a Pan Am logo and shorts with a Pepsi logo.
http://www.tracksuperfan.com/five-things-we-learned-in-new-york
It occurs to me that you used to see all sorts of these kinds of advertisements on road runners in the 1980's. I guess these days it would be OK for a singlet to say Saucony at the NYM, but the other logos would be forbidden.
Obviously something has changed in the meantime, I assume with the IAAF rules now being applied to the NYM.
I wonder why that was and when it happened?