Visible crew/equipment: While Phil and Claire are warming up for their race, Alex and Luke are getting dropped off. When you see them walking towards Phil and Claire you can see a crew member with equipment behind the bushes at the right side of the screen. (00:17:05)
Visible crew/equipment: In the scene where Dylan visits Haley at home, when Claire grabs Dylan as he's going up the stairs you can see a member of the crew (probably the man holding the mic) in the mirror in the background behind Claire. (00:10:40)
Disneyland - S3-E22
Revealing mistake: The episode was filmed with real Disneyland visitors. One can constantly see them staring at the camera and/or Disneyland cast members standing with their backs to the actors, monitoring the crowd. This is especially noticeable when the family first arrives and when Mitchell and Cameron talk about Lily's leash: behind the actors, there are long white rope lines supervised by park staff to keep visitors at a distance. Several people can be seen filming the actors or taking pictures with their phones.
Visible crew/equipment: When Manny holds up the Phantom mask to Jay's face and realises it's for the wrong side, as Manny rushes back upstairs for a lefty, the reflections of the Steadicam operator and crew are visible on the minivan's surface, beside Gloria. (00:14:40)
The Incident - S1-E4
Continuity mistake: When Dylan arrives at the Pritchett family dinner, and Phil notices that he brought his guitar, Dylan's gig bag switches shoulders between shots.
Continuity mistake: When Jay is talking with his brother and finds out about his brother's cancer, he is holding a glass of scotch with a tiny bit of ice. When his brother approaches him the glass now just has ice with no scotch. We don't see the glass for a short period before he is about to sit in his chair and spills the contents of the glass, which now has the scotch and ice again.
Visible crew/equipment: After Gloria and Andy's scene at the park, when it cuts to Pepper presenting his unique wedding ideas, in the first two shots facing Mitch and Cam, the yellow T-mark taped to the floor is visible at the bottom, left corner of the screen. (00:03:35)
Answer: He has seen himself dancing, and is mortified at how bad he looks.