Visible crew/equipment: When Squad 51 is dispatched to the "possible heart attack," just as the squad rolls up on scene, we can see its real license plate with number 70324H, instead of the prop plate number E999007.
Visible crew/equipment: When the dispatcher drops tones for the 'possible heart attack', just as we hear Captain Stanley respond, "KMG365," we can see movement between Engine 51's front driver and passenger seats, where the camera is located. Captain Stanley is still at the radio base station and Mike hasn't opened the door yet.
The Tycoons - S5-E23
Visible crew/equipment: When Squad 51 is dispatched to the baby with difficulty breathing, in the wide shot when the squad pulls into the driveway and heads to the front of the house, the cameraman steps out of the shadows on the right side of screen and walks toward the squad (then it cuts to the footage he was shooting), and in the next shot as the moving camera closes in on the squad in front of it, the cameraman's shadow becomes visible on the tree and house.
School Days - S2-E14
Visible crew/equipment: When Roy walks into the kitchen late at night, while Billy's alone on the couch studying about emergency medicine, there are moving shadows on the floor towards the left of the screen.
Peace Pipe - S2-E5
Visible crew/equipment: Just after the drunk driver is loaded onto the ambulance, when Roy tells Johnny about Debbie's pulse and respiration, and that she's in bad shape, then also when Roy tells Captain Stanley to make it quick, a crew member sitting atop a ladder with set lighting beside him are visible in the background.
Cook's Tour - S1-E4
Visible crew/equipment: After Roy and John pull up to the house with the woman in labor, when the deputy pulls up behind Squad 51, the reflection of production equipment alongside the lamppost is visible on the car's surface. In the previous long shot of the house, we see there is only a large area of grass in front of the house.
Visible crew/equipment: When Roy and Johnny are with Dixie, they see the new unit and scanner at the base station, and when Roy walks over to it, the actor's white tape mark is visible on the floor where he stands.
Visible crew/equipment: When Johnny chases Harriet down the street, behind Johnny we see Roy backing up the squad to follow them, with nobody around, then when it cuts to the view from within the squad, the reflection of crew is visible in the driver's side mirror.
Visible crew/equipment: When Roy gets the little girl, Angie, out of the wrecked airplane and then places her in the Stokes basket, the outlines of the mic transmitter and wire are visible on the back of his shirt.
Visible crew/equipment: When Brackett, Dixie and Early are working on the unconscious little boy, once Brackett says to go with the pacemaker, multiple black T-marks are visible all over the floor - three under the gurney and one near the cart. Another actor's white tape mark is visible under the gurney (partially blocked by the green oxygen tank), where both Early and Dixie stand at different times.
Fair Fight - S6-E5
Visible crew/equipment: After the cave-in rescue, when Dixie, DeSoto and Gage are in the ER, Gage washes his face and as he comments that he wasn't cut out to be a mole, two tape marks are visible at his feet.
Visible crew/equipment: When Mr. Grady (self-defense instructor) is in the ER, being examined by Dr. Brackett, there is a visible T-mark on the floor behind Gage.
Visible crew/equipment: After Chet is brought to the ER, Gage goes to the nurses' station. When Brackett opens the door and walks out of the base station booth, the actor's T-mark is visible on the floor behind him.
Visible crew/equipment: When Brackett's helicopter takes off the filming helicopter can be seen through the window. (00:03:45)
Visible crew/equipment: When squad 51 parks upon arrival at the gas station the array lighting is visible on the driver's door.
Captain Hook - S6-E8
Visible crew/equipment: After Station 51 is dispatched to "aircraft down," just as the squad and engine roll up on the scene, the reflection of the camera crane can be seen on Engine 51's windshield.
The Promise - S3-E11
Visible crew/equipment: After Squad 51 is dispatched to 'woman down', just as the squad rolls up in front of the apartment building we can see a bit of the camera's production equipment at the bottom left corner of the screen, which is then pulled quickly out of shot.
How Green Was My Thumb? - S3-E17
Visible crew/equipment: Just as Roy opens the door to Mrs. Johnson's apartment and he and Johnny walk in, the shadow of production equipment (looks like a reflector screen on a tripod) is visible on the wall behind them.
Visible crew/equipment: During the structure fire, after Roy finds the boy and his dog under the bed, when Roy heads down the stairs and then rushes back up, as he gets to the top of the stairs when the camera pans to the left we can see the barndoor set lighting, at the top left side of the screen.
Visible crew/equipment: On site at the construction accident with the back injury victim, when Roy climbs over the tower's railing we can see the yellow canvas strap attached through the leather loop of his lifebelt, but when he descends to the injured victim, the yellow canvas strap is now also attached to a carabiner protruding from under his turnout coat, by his pants, which presumably is attached to additional hidden support.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy