When Will gets pulled over for running a red light, Capt. Stone's seat belt is on and off between takes.
When notifying Olivia of her husband's death, Captain Stone tells her, "You're listed as the NOK on your husband's forms." NOK is an acronym meaning "Next-of-Kin". Casualty Notification Officers are instructed not to use acronyms when making a notification, as the Next-of-Kin might not understand them.
Montgomery wears an armor crest as his branch insignia and also wears a Combat Infantry Badge. Since his branch insignia crest represent that he is an armor crewman and not infantry, he should not be wearing a Combat Infantry Badge. Only the infantry can wear a Combat Infantry Badge after being awarded the badge while in combat.
SSG Montgomery should have at least two service stripes on his left sleeve, in addition to the missing Overseas Service Bars. Each service stripe denotes 3 years of service and he'd likely have at least 2 of them.
Several times throughout the movie, Captain Stone notifies next of kin of deceased soldiers without first getting positive confirmation that they are, in fact, the soldier's next of kin. Casualty Notification Officers are required to make sure that the person they are addressing is actually the next of kin before making notification. This is not a mistake that a professional like Captain Stone would make.
Staff Sergeant Montgomery tells the recruiting sergeants in the mall to take a walk, and one of the sergeants replies, "Yes, sir." Only officers are referred to as "sir." A sergeant addressing another sergeant who outranks him would simply say, "Yes, sergeant."
Captain Stone claims to have served in Desert Shield and Desert Storm, but does not have a "combat patch" on his right shoulder.
(at around 1 min) Capt. Tony Stewart and SSGT Will Montgomery enter the house and sit on the couch without removing their caps.