Real-Life Relative: Walter Matthau's son David plays Ross (the CIA agent who Kendig briefly holds hostage) and his stepdaughter Lucy Saroyan plays the seaplane pilot (who tells Kendig that he reminds her of her father).
Throw It In!: Sam Waterston had to delay filming his scenes for this film because of the infamously bloated shoot of Heaven's Gate that ran way over schedule, and flew to England for Hopscotch with no chance to rest or recover. Since he looked so tired and haggard, some lines were added to the script of characters telling Joe how tired he looked (which he chalked up to jet lag).
