When McGee and Tony are in the car you can clearly see that they are not driving and being towed instead, plus the green/blue screen out of their car windows do not match up and in parts is jumpy.
When the crew is processing the crime scene with the corpse in the skeleton costume, both Tim and Tony detect something in the room. It turns out to be a robot vacuum cleaner, but those things are very loud and they would have heard it as soon as they walked into the room.
As Abby identifies Lee Varon in her lab with her back to the camera and Tony staring at her on her left, a crew member in a red shirt and glasses can be seen over her right shoulder.
When Gibbs is in the wounded man's house, crew is visible in the mirror.
When it is realized that the little girl is missing, Tony says, "Amber alert. On it, boss." and leaves to activate the alert. But he never gets any information about the girl, such as height, hair color, what she was wearing, etc.