Continuity mistake: The mailbox is roughly parallel to Richard's SUV but is more perpendicular when he looks at the address number, then it is back to parallel. (00:06:40)
Deliberate mistake: Richard falls (or is pushed) into the lake, and a loud splash is heard. However, as he pulls himself onto the deck, no water drips from him. But there is already a large wet area further onto the deck when the sheriff tosses him. (00:18:05)
Trivia: Richard's New York MD license plate has the "Statue of Liberty" along the left side. MDs with the special plate usually (if not always?) have the "Universal Symbol of Access" between the letters "M" and "D", as well as "Physician" written along the bottom of the plate. [Possibly a "factual error."] The "Universal Symbol of Access" allows some otherwise unauthorized parking areas to be used and extends parking time. (00:34:58)