Revealing mistake: When Grissom and the Coroner are discussing the short cadaver's injuries you can see the little guy breathe between takes.
Continuity mistake: When Sara has finished processing Melanie Grace at the slot machine, Melanie gets down from her chair and a uniformed officer can be seen helping her down. However in the next shot the officer has disappeared completely.
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.