Heard a similar story from a buddy who shoes polo ponies. A trainer pointed out he was setting the nails a touch too high, making the clinches weak. He adjusted his hammer swing just a bit and the shoes held way better through a full chukker.

Actually, I see it a bit different from @bethwhite. I mean, in my experience, pulling out a whiteboard just adds another thing to carry and clean. By the time you draw it, the moment's kind of gone, you know? Maybe it's just me, but a quick finger-draw in the dirt or on the truck's dusty side has always worked fine.

Maybe he just wanted it to be perfect.

Wait, you guys are still not using layer states for that?

Yeah, and that's just one brick (a whole wall is wild).