Continuity mistake: We see Fornell handing Gibbs a beer at his house and his phone is in his right hand. When the shot changes, his phone is now in his left hand. (00:10:40)
Visible crew/equipment: At the naval yard when Ducky is exiting the cab, as it drives off you can see an orange tape marker on the floor. (00:24:30)
Continuity mistake: When we see Ducky arriving back at the naval yard, two men walk past his cab but when the shot changes, they walk past again. (00:24:20)
Continuity mistake: When Ziva is on Tony's shoulders, she goes from grimacing and looking at the floor to looking above her and not grimacing as much instantly. (00:04:00)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.