When Grissom goes into the bathroom of a suspect, the toilet seat is down when viewed from the door, but as Grissom approaches, the seat is up, then when he goes to inspect the toilet he raises the seat.
The homeowner put on the dead man's left sneaker to kick the door in, but a right sneaker is seen kicking the door in.
Brown is suspended for dereliction of duty for leaving Gribbs alone at a crime scene. Grissom did the exact same thing earlier. Grissom was more negligent since he was a senior officer, and unlike the robbery there was no officer at the liquor store, whose owner also pulled a gun on Gribbs. Grissom would have faced similar discipline.
Grissom should have asked the lady to sign the waiver for personal injury before he took her blood.
A trainee CSI would not be left alone on their first day on the job (this was done by both Grissom and Brown). Like law enforcement officers, they would be assigned to a senior CSI for field training.