Character mistake: Mark walks into the house and is surprised to see Cody there, and remarks that he heard he was back. However, just before this, when Mark entered the house, Cody's van - which Mark had to walk by to enter the house - was visible through the open door, so that should have confirmed it for Mark before he saw Cody in person.
Visible crew/equipment: When Cody is saying to Mark "You know it's really good to see you're dating," a crew member steps into the shot on the right side of the screen. (00:08:45)
Visible crew/equipment: When Cody is handing Carol the cashier's check, a camera and a crew member's arm are briefly visible on the right side of the screen.
Answer: I could be mistaken, but when the series debuted, its premise was something along the lines of "A divorced contractor and a widowed beautician impulsively marry." If that is true, then the Foster children's father is dead. As for Frank, it could be that his wife was an unfit mother and is therefore not in her children's lives. Perhaps the writers felt addressing these issues would lead to more questions, or at the least require characters to bring up the unseen parents more in conversation, so perhaps they felt it was just better to never talk about them at all and let any discussions about them remain off-screen.
Phaneron ★