Other mistake: Season 10, episode 4 "Coup de Grace": When Nick is doing the phenolphthalein test on the q-tip, it turns pink immediately and starts to overflow pink coloring all the way down the side of the stick, which is not how that test works. Normally it takes a few seconds and only turns color around where the blood is.
CSI: Crime Scene Investigation (2000)
1 other mistake in Coup de Grace
Factual error: In a number of episodes people are shown eating and drinking in the laboratories. For instance, in "Miss Willows' Regrets" Nick and Greg are seen eating fried chicken in the lab, and in "Overload" Sara eats a sandwich while watching Grissom experiment with her deli pickle. There are other examples. No reputable laboratory (which this is supposed to be) would allow its staff to eat or drink while in the lab. It is basic scientific protocol to prevent contamination of samples or the person picking up toxins on their food.
David Hodges: You know, you and me, we're not the marrying kind. The intricacies of our nature can't be understood by just one woman.
Gil Grissom: Would you close the door, please?
[David Hodges shuts the door with himself still in the office.]
Gil Grissom: From the other side.
Abra Cadaver - S3-E5
Trivia: This episode featured a guest appearance by Tom Noonan. Noonan and series star William Petersen played villain and hero, respectively, in the film "Manhunter."
More questions & answers from CSI: Crime Scene Investigation
Answer: He doesn't have the authority to arrest him - when anyone is arrested in the show, a police officer does it. Also he tells Ty that he is going to be submitting his case findings to Ty's insurance company, who would no doubt contact the IRS, who then would have him arrested for fraud etc.