Continuity mistake: When Susan arrives Hal is holding Jaime, and the baby's entire body changes position between shots repeatedly - in some shots the front of Jaime's body faces Hal, yet in others Jaime's back faces Hal.
Revealing mistake: When Lois confronts Susan about not telling her about Susan's kidney disease, Susan is telling Jamie how cute he looks in his sailor outfit. When the camera is moved to a different angle, it becomes very obvious that "Jamie" is just a prop baby doll. (00:11:10)
Answer: Francis is only allowed to talk on the phone at school for three minutes a day. I think the code gives him free access to talk to his girlfriend.