Continuity mistake: In the Episode "Sharif Returns" When Ducky shows Gibbs the eye in the gladd vial, it alternates between being completely submerged in the fluid to sticking out the top.
Continuity mistake: When Gibbs drops the nails on the food carton, the position of the nails goes from spread out to grouped together instantly. (00:19:50)
Continuity mistake: During the scene where Gibbs chases Shariff into the railway station restroom, Gibbs' position on The Wall changes, his gun hand passes the corner of The Wall at least three times. Also as he starts to fall to the floor, the long shot from low angle close to the urinals shows Gibbs holding the gun with both hands and they are moving to his right, his left shoulder going into he wall. At the cut, the gun is in his right hand only and moving across his body to the left and his right shoulder is now going into The Wall. The shot cuts to Shariff, who has moved about a foot to his right during the cut, then cuts back to both Gibbs and Shariff, Shariff has returned to his original position and the gun has moved to Gibbs left hand, although we don't really see the gun until he falls and Shariff picks it up, thus ruling out the possibility of the gun being dropped before he falls. (We do hear the gun hit the floor as he falls.) (00:40:10)
Continuity mistake: When Sharif calls Gibbs to gloat, when Sharif ends the call, the shot cuts to Gibbs closing his cell phone, shot cuts to McGee and Col. Mann, when it cuts back to Gibbs, he is closing his phone again. We can even hear the phone close both times. (00:33:10)
Continuity mistake: When Abby is talking to Gibbs about getting a tattoo, he goes from looking at her computer screen to her in between shots. There's a straight cut, so there was no time for him to turn his head. (00:06:55)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.