In the park where Frank is hiding behind trees while Laurel times him, Frank stands three times by a black car. The license plate on that car changes from California to Manitoba and back to California.
When Frank tells Tom his occupation in the toll booth, Tom's hair alternates between being neatly parted and windswept several times.
The Amtrak station appears to be near downtown Buffalo. An announcement is made about a train going to Cleveland. Trains in downtown Buffalo only go North and East. Westbound trains only leave from a suburban station in Depew, NY.
When Frank and Laurel first meet in the mortuary, the dead body's stomach move up and down as he's breathing.
The supposed Buffalo train station is full of Via Rail Canada signs, but no Amtrak sign, even though an Amtrak train announcement is heard on the soundtrack.
When Frank and Laurel are sitting in the mall (food court), addressing envelopes to the next of kin he killed 'wrong' , there is a store sign in the background, Telus, a telecommunications company based in Canada, which does not serve the US, let alone San Francisco.
The story that Frank tells regarding the assassination of William McKinley is incorrect. President McKinley was indeed assassinated in Buffalo as stated, but the rest of Frank's story regarding the shooting and the search for the bullet in his body actually refers to the facts surrounding the death of President James A. Garfield.