Other mistake: Season 5, Episode 12, "Stakeout": The picture on McGee's camera phone is just wrong. It shows not just the man in front of him, but it also shows a hand, holding a camera phone - McGee's camera phone. In other words, the phone is showing a picture of itself and the man, instead of just the man. (00:40:25)
Other mistake: When McGee tells Gibbs that Nelson erased his entire hard drive, the camera shows the diagnostic he is running - "Primary Drive Erased: 100%." Yet the details below show 93GB used of 111GB total, and the drive letter is G: (not C: as it would most likely be.) It could be argued that his C: drive is simply an OS drive, and G: is his data drive, but still, 93GB used is not 'erased'. (00:22:05)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.