Factual error: In the scene where Hodges describes the camera glass to Grissom, he states that camera lenses are curved on one side and flat on the other for a higher refractive index. The refractive index is a property of the glass and has nothing to do with its shape. Also lenses used in cameras can have any shape to them, with even a moderately good lens in a compact camera being made of several pieces of glass with few flat surfaces. This is not modern technology in camera lenses, they have been made like this for decades. Narrowing it down to a non-compact camera by Nikon, Canon or Leica is also wrong, as all manufacturers use these techniques.
Living Doll - S7-E24
Factual error: When Nick and Katherine are examining the bloody prints in the bathroom, Katherine looks at the wall outlet and says there are no burn marks present, when smudges are visible around the socket, and the wall next to it.
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.