Visible crew/equipment: When Gibbs and Ziva are in the "safehouse" Ziva set up for Ari, a crew member and his boom microphone are seen on the left of the screen, right before Gibbs climbs the ladder to remove the hidden camera spying on them. (00:30:10)
Other mistake: When the old well needs filling in, for safety reasons, Ryan is breaking up bricks. If you are filling up a well, first, you'd need lots of bricks and stones, heaps more than Ryan's small pile, and, two, why does Ryan have to break up the bricks? They're going into the well - it doesn't matter if they are big or small.
Thrill Kill - S5-E1
Factual error: When Dylan gets out of jail, a palm tree can be seen in the background behind him. This reveals that the scene was filmed in Los Angeles, not Philadelphia.
Continuity mistake: Jamie and Adam are shooting at Police badges to see which one would potentially stop a bullet. When they get to the third badge, it is held up to the camera. It says 'Jamie Hyneman' on the badge. The badge is then shot, and shown again to the camera. This time the engraved writing on the badge has changed to 'Adam Savage'.
Revealing mistake: In brother Justin's padded cell, the far wall is obviously a painted backdrop. It even flutters when the orderly and doctor walk in! The only solid part is a couple of feet at the end, that Justin leans up against.