Continuity mistake: When Lois is yelling at the boys for playing with fire, the location of the green scissors on the table keeps changing between shots.
Continuity mistake: When the boys are wrapping their parents present, Dewey is holding a bow in some shots and not holding one in other shots.
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.