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 Malcolm is trying to get the TV back to the channel he was watching, he picks up a big remote and finds the channel which the video camera feed is on, but the remote he is holding on the TV is a smaller one. It then cuts back to Malcolm who is moving his hand away from the remote he just put down and it's the bigger one again.
Continuity mistake: In the scene where Lois finds out about Francis escaping, there are three orange mugs hanging from a rack by the phone. When Lois reaches for the phone to call the police, she makes the middle one start swinging. She and Hal sit down, and the end mug has moved from the rack into a box on the kitchen counter. Also, the mugs are hanging still. Towards the end of the scene, the "fallen" mug is back on the rack, and the middle mug is swinging again.
Continuity mistake: When Malcolm is in Stevie's room eating cookies, the cookie in Malcolm's right hand disappears and reappears between shots.
Continuity mistake: During the fight between Malcolm and Spath, Spath goes at Malcolm with his right fist, but the closeup of his hand going towards Malcolm and Stevie is his left hand.
Continuity mistake: When the "Krelborne" teacher comes to the house to tell Lois that Malcolm is gifted, Lois comes to the door naked and puts her arm up on the doorway. On the shot from behind she has her hand low (about where her waist is) from the shot from the front she has her hand up high (above her head).
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.
Continuity mistake: In the scene where Lois and Hal tell Malcolm he is going to the "special class", Hal notes that the pitcher of iced-tea he makes is always empty, and says, "Look at that - gone," before placing the lid back onto the pitcher. Yet, when it cuts to the wide shot of the table, the pitcher lid is by Hal's elbow. (00:17:50)
Continuity mistake: While Dewey stands on the table, Mrs. White (Bea Arthur) dips her finger in the bowl of chocolate and draws a mustache with it on Dewey. In the following shots the chocolate on Dewey's face differs.
Continuity mistake: When Julie passes through the kitchen to get Malcolm, Dewey and Egg are in there cleaning the floor they have suds all over the floor, When Julie runs back through after seeing Malcolm in his underwear she slides across the floor, The floor is still completely covered in suds but when she gets up if you look in the background you see the floor with hardly any suds anywhere. She could not have soaked up all the suds when she slid across.
Continuity mistake: When Lois is in the bath tub soaking after getting upset about the family wanting to go to the funeral. Dewey comes in and ask for juice. When they are on Lois(front view) the suds barely come to the top of her breast. When the show Dewey (side view of Lois) The suds are all the way up to her shoulder.
Continuity mistake: When Lois is packing lunch in the blue cooler her hands go from on the side of the cooler to down by her waist in one frame to the next. No time for her to move it.
The Bots and the Bees - S1-E14
Continuity mistake: In the scene where Malcolm and the Krelboynes are talking and watching Robots after the opening credits. There is a blue schoolbag on the table but after it is gone, but when we see the table again the schoolbag is there again.
Continuity mistake: When Malcolm and Reese talk about April at the water park, there's a girl with a blue shirt and a towel tied around the pelvis who passes behind Malcolm twice in two different shots.
Continuity mistake: When we see Dewey's friend at the table eating cereal he is eating cereal and the bowl is full of milk. In the next shot the bowl is full of cereal and there is barely any milk.
Continuity mistake: Hal speaks about having held Malcolm the moment he was born. But in the Season 2 episode "Flashback" not only was he not there for his birth, he didn't hold him immediately, instead he talked to Lois.
Continuity mistake: During the scene when Lois says that Malcolm is a genius, his arms keep changing position between shots.
Continuity mistake: When Malcolm goes into the classroom and gives his teacher a hamburger she eats about half of the burger really quickly but in the next shot of the hamburger there appear to be only a few bites taken.
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.