I was on a film once where someone was counting the heads of people in crowd scenes I'd drawn to know how many extras to hire. I was stunned when I heard that. I was just randomly drawing people to fill up the panels. There's a guy I know who actually puts a disclaimer on the front page of his storyboards saying that these are a guide. Costumes may not look like this. Hairstyles may not look like this. These aren't like the Bible!