In the level "Boarder Crossing" Sam is searching for documents so sensitive that they are not even stored in computers. Two of the documents can be found in standard, unlocked filing cabinets while the third is found inside an open backed truck.
In the Splinter Cell games Anna Grimmsdottir is from Boston, MA and, as voiced by Claudia Besso has a distinct Boston accent. In Blacklist she is voiced by Kate Drummond and has a distinct Canadian accent.
In the level "Private Estate" Sam enters a security room and sees several monitors showing CCTV footage from around the property. Charlie even hacks into the CCTV system to inspect the property to help Sam get through the level. Yet as Sam moves into the property he encounters no cameras inside or outside the house.
The mission Private Estate takes place at least 5 or 6 days before the mission Detention Facility. A full moon is seen in both levels but in that amount of time a full moon will wave become a 1/2 moon and would be much less bright.
At the start of the level LGN Terminal Sam jumps from the plane with no parachute and instead is tied to the plane with a rope. When he lands he has a parachute and the rope is gone.
The Paladin has holding cells to lock up prisoners. This is in violation of FAA regulations that state every person on an aircraft must be able to get off the plane by themselves in case of accident. Locking a person in a cell on an airplane is not legal.
At one point the co-pilot states that two pilots are required to fly the Paldin. No airplane requires two pilots. FAA regulations require two pilots for some aircraft based on size, but this is for safety only. Even the largest planes can be flown by a single pilot in an emergency.
At one point all four engines on the Paladin fail. The plane then goes into a steep dive. To be declared air worthy by the FAA an airplane must have a minimum glide ability that could, at least in theory, enable a safe forced landing.
In some levels you can hear snipers checking in every few seconds via radio ("This is sniper (#). All clear.") Though this is to let the player know to watch out for snipers, in the context of the game this constant checking in would be to ensure whoever the snipers are protecting that they are still alive and active. If Sam neutralizes a sniper his failure to check in should trip an alarm, but it never does.
In the briefing for "Special Missions" Fisher states that the President will declare war. The US President can not declare war. He or she must ask Congress to declare war.
Mr. Fisher's gear has glowing objects that would give away his position.
Knockout gas only affects hostile NPCs; it should affect anyone not wearing a mask.
In the Iraq Mission the loss of the drone did not alert the hostile NPCs.
The Engineers pin down firemen at the liquid natural gas facility. Since the Engineers are the only ones that are armed, it makes no sense that they didn't just move in and shoot the firemen.