Factual error: At Shea Stadium, in Queens New York, Carrie asks Arthur if he want a Coolicoo. Carrie then goes to the concession to buy Coolicoo's and tells the guy behind the counter she can see them next to him. However, Coolicoos don't exist at Shea Stadium. They are only available at Dodgers Stadium in L.A.
Continuity mistake: In the exterior shot of Coopers there is a car parked, no bins, no people. However, in the immediate interior shot, you can see a garbage bin, newspaper box and people walking by in either direction. (00:13:15)
Continuity mistake: When Ritchi and Spence are at the cafe, Spence pours the remainder of the pitcher into his cup. The shot goes back to him, and it appears he took a large sip because his cup is near empty. When Doug and Deacon come in, Spence's glass is almost full again.
Revealing mistake: When Doug and the rest are at a ballgame, the man sitting behind them is eating a hot dog. Actually he's pretending to eat, it never shows any bite marks and the guy is pretending to chew it.
Continuity mistake: At the ball game right before Carrie gets to the front of the concession line, there is a woman right behind here followed by a man. When she gets to the front of the line, the extras behind her have switched.
Answer: Sara hasn't been mentioned in later episodes, and it suggested in later episodes that she never existed, and that Carrie is an only child. Kevin James stated that the producers couldn't think of an good plots to use with Sara, so they left her out.