Other mistake: At the beginning when Festus rides up and finds Riley Sharp handcuffed to the hitching rail, if you notice the handcuff chain is draped over the top of the hitching rail and there is nothing preventing him from sliding the chain off the end of the railing.
Gunsmoke (1955)
1 other mistake in The Intruder - chronological order
Starring: James Arness, Ken Curtis, Amanda Blake, Milburn Stone
Visible crew/equipment: When Chester and Cassie are in The Cabin, Chester is looking through the picnic basket while Callie holds on the Indian's hand and talks to him. In the scene behind Callie is an unidentified "cowboy" who appears twice and then disappears when the scene cuts to Chester the 2nd time. (00:47:00)
Kitty Russell: Matt, you can't account for everything that happens to people who touch you. You know, I learned a long time ago, there are some things in this life that you just accept the way they are.
U.S. Marshal Matt Dillon: That's pretty deep for a redhead.
Kitty Russell: I'm a pretty deep redhead.
Trivia: Although they played father and son in this episode, Jack Elam was only six years older than Harry Dean Stanton.