Mat Matthews removes a napkin off his neck and drops it on the floor and Jessica asks the waiter to pick it up. When Arnold Wynn enters the restaurants, the napkin has jumped back onto Mat's neck and in the next scene is off again.
The return address for Stewart Murphy is shown as "Buffalo, NY 10203." This is not valid for Buffalo. ZIP codes for Buffalo start with 142, e.g. 14201. 10203 is a zip code for lower Manhattan in New York City.