Continuity mistake: When Grissom's car window is broken in the first shot where you first see the break there is hardly any glass left in the frame and yet when he is at the gas station there is an almost perfect circle of broken glass and a lot more in the frame.
Visible crew/equipment: While Grissom is searching the car in the barn, a red laser light shows up on his left arm and dances briefly around the car for a couple seconds. This is caused by camera equipment in film. (00:26:25)
Other mistake: When Grissom's vehicle is shown driving to Jackpot, Nevada, he is shown to be driving on the wrong side of the road. (00:03:15)
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.