I remember seventh grade shop class, in 1971, the teacher asked us how big a 2 by 4 was. I was the only one who knew. I said “One and five eighths by three and five eights”. I had learned that from my Dad, whose father was a carpenter, a few years before that.
In fact I have used the example of the 2 x4 more than once to point out how “trade usage” can refer to a product that is not literally what it is called, but would be understood in the trade as to what it really was, so that if someone contracted to buy 2 by 4s and you gave 1 5/8 by 3 5/8 you would have met your obligation.
I never in my life thought that a judge would actually rule this way.
Then again it’s Marin.
BTW, the two by fours in my house, built in 1910, are two inches by four inches.
Now I'm wondering if "Marin" is Spanish for "moron".