Other mistake: On scene at the traffic accident, when the woman and the boy with non-serious injuries are seated at the back of the ambulance, neither Roy or Johnny are going along with them to Rampart, yet Johnny puts the drug box inside the back of the ambulance with them, and the ambulance drives off. With their drug box! Captain Stanley even says that he'll advise dispatch that they're available for a run at the scene, while the guys will be looking for the dog.
Visible crew/equipment: While Roy and Johnny are climbing up to rescue the boy on the bridge, there's a closeup of the boy as he breathes heavily. When this shot pans to the right we see Roy (his stunt double actually) place the rope behind his back, and a mysterious dark gloved hand quickly appears behind Roy (and it's not Johnny's hand).
Visible crew/equipment: When Gage and DeSoto are driving away from Rampart, discussing DeSoto's possible purchase of a new house, dispatch calls about a traffic accident. In this exterior closeup shot of Squad 51, the reflection of the camera's flatbed vehicle is visible on Squad 51's red surface.
Continuity mistake: Squad 51's lightbar has a center chrome piece which has slats at the front and is solid at the back. When the squad's dispatched to the vehicle accident with the two student drivers, on scene the lightbar's chrome center is on backwards, it's solid at the front for some inexplicable reason.
Visible crew/equipment: After Roy and Johnny speak to Chet's friend the realtor, when Station 51 is being dispatched to the accident on Harbor Freeway, in the overhead shot of the apparatus bay, we can see the shadow/reflection of production equipment moving on the engine's windshield.
Visible crew/equipment: When Station 51 is dispatched to the rescue on Johnson Canyon Bridge, just as Engine 51 rolls out of the apparatus bay, the reflection of array lighting and two reflector screens are visible on the engine.
Continuity mistake: After Roy gets his leg bandaged at Rampart, as he and Johnny exit to their truck, they suddenly get haircuts. Looks like a shot from an earlier season.
Continuity mistake: When Station 51 is dispatched to a structure fire (with the two girls trapped upstairs) the address given is 1911 Harper Ave, but when they reach the house with the fire, directly across the street that house number is 1637.
Emergency! the Wedsworth-Townsend Act: Part 1 - S5-E15
Character mistake: When Johnny and Roy are in the kitchen and start reminiscing about when they first met, Johnny recalls those days and says "I was working B shift at Station 8's," however, Johnny was actually working at Station 10.
Visible crew/equipment: When Brackett's helicopter takes off the filming helicopter can be seen through the window. (00:03:45)
Visible crew/equipment: After landing at the base camp, when Brackett and the others walk away from Copter 10 we hear the comment, "The coffee's lousy but the food's great," then we get a bird's-eye view of the base camp, and can see the moving shadow of the filming helicopter at the lower right corner of the screen. (00:06:20)
Visible crew/equipment: After Engine 51 and Copter 10 are dispatched to the "traffic accident with injuries" Engine 51 is instructed to switch to frequency 3, and when Copter 10 takes off with Brackett, the moving shadow of the filming helicopter is visible near the shadow of Copter 10 chopper. (00:09:10)
Visible crew/equipment: While Brackett is on Copter 10, after the dispatcher tells the pilot that the truck driver has been heard on the CB saying that he's trapped in the cab, repeating the same location, when we see the bird's-eye view of Copter 10 flying below, the shadow of the filming helicopter is right beside the shadow of the Copter 10 chopper, at the top of the screen. (00:11:35)
Visible crew/equipment: During the fire late at night, after Johnny and Roy run to the burning house, when Captain Stanley tells Chet to get the exposure and later warns to watch for spot fires, the moving shadow of the cameraman/camera is visible on the ground, right beside Captain Stanley's shadow.
Visible crew/equipment: At the site of the vehicle accident, the outlines of the lavalier mic and wire are visible on the back of Roy's shirt, particularly when he's with Eddie as his father's being taken in Copter 10 to Rampart.
Visible crew/equipment: After Captain Stanley and Roy get the trucker out of the wrecked cab, when Stanley takes his pulse, the outlines of the lav mic transmitter and wire is visible on the back of his shirt.
Continuity mistake: When the unconscious boy is brought to the ER, he's taken into treatment 2, with a windowless door, but when Early is doing the lumbar tap on the boy, the door behind Early has a window, and also by the way the room is set up, we know it's treatment 1 he's in, not 2.
Continuity mistake: When dispatch drops the tones at night, waking all the guys up, notice that Marco's mustache has vanished, though it reappears later. Additionally, they all get into their boots, turnout trousers, only white T-shirts, suspenders, and grab their dark jackets, but when the bay door opens they're dressed in their uniforms as they respond. Then at the fire they're in the turnout trousers, and Johnny and Roy are wearing the uniform shirts when working on the burn victim.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When Brackett and Morton go to the outdoor eating area to speak with Nancy's father, just as Brackett sits down and crosses his legs, the actor's T-mark is visible on the floor in front of his chair.
The Girl on the Balance Beam - S5-E18
Other mistake: The dispatcher gives the address of "woman trapped on a wire" as "Commercial Studios,1122 Dellini Plaza", and as Engine 51 drives past the front gates, the large sign reads "World Pictures Corp." Additionally, the address of World Pictures Corp is 1731 Carlson, when we see the same footage of Engine 51 driving past the sign in episode "The Exam" in season 6.
Answer: I was rewatching a few first season episodes of Charlie's Angels (1976), and in S1xE6 "The Killing Kind," I recognized the same actor. So, to finally fully answer your question, the two baseball players in School Days are played by Rod Perry and Sean Fallon Walsh.
Super Grover ★