It was in the 40’s, I read an article a few years back detailing it, I can’t seem to find the Penalties incurred anymore when searching the Internet, But I am Positive a few went to PRISON
Ok, it was a long time ago.... before my time
I think there was also a similar situation among glass manufacturers that were prosecuted for rice fixing. It resulted in little books with list prices for every inch in length and width that were discounted at the time of sale. That was the Late 40’s I think