In "The Lottery" by Shirley Jackson, what happens if someone misses or isn't present at the drawing?

When someone misses the drawing, another family member must draw on his or her behalf.
During the proceedings, Mr. Summers, the man who presides over the lottery, must ensure that everyone is accounted for. On one particular occasion, a man named Clyde Dunbar is absent. Accordingly, Dunbar has broken his leg, and so, he cannot attend the drawing. Mr. Summers asks who will draw on Dunbar's behalf, and Dunbar's wife answers that she will do the honors.
Upon hearing this, Mr. Summers asks whether Mrs. Dunbar has a grown son who will draw for his father. She responds that their son, Horace, isn't sixteen yet and therefore, cannot draw for his father. Interestingly, even though everyone in the crowd knows that Horace isn't of age, Mr. Summers must follow protocol and formally ask the necessary questions when someone is absent.
Mr. Summers then asks whether the "Watson boy" is drawing this year. The boy answers in the affirmative and confirms that he will be drawing for himself and his mother. Interestingly, there is no explanation for why a young boy can draw for his mother but Horace cannot draw for his father, Clyde. As the story progresses, however, we get the idea that tradition is extremely important to the members of the community. The people are willing to keep in place the arbitrary rules and rituals that dominate their lives, so long as things can continue as they always have.