Revealing mistake: At the apartment complex where the jet fighter had crashed there's an explosion, and when one of the firefighters becomes engulfed in flames his helmet falls off, and the special fireproof headpiece that the stuntman is wearing is visible.
Visible crew/equipment: Just after Herbert leaves the station in the morning, dispatch sounds the alarms, and when Roy and John are in the squad while the dispatcher begins talking, there are nice reflections of the camera, reflector screen (in the background), and crew members/cameraman who move around, that are visible on the surface of the spotlight. Additionally, the shadow of the boom/mic is perfectly visible on the windshield as it moves down.
Visible crew/equipment: When the guys wake up in the morning and walk into the kitchen, the clear reflection of the camera dolly is visible on the oven glass door as it trucks to the right, when the guys see the empty mouse trap.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy