Razvaluha

Corrected entry: Henchmen are shown flying a helicopter over DC, with automatic weapons and such. After 9/11, DC has very strict airspace security, and a helicopter flying around without broadcasting its position would be beset by fighter jets in no time at all, especially if the helicopter was carrying armed men.

Razvaluha

Correction: The hackers have access to all communications so could therefore prevent the summoning of any jets. Not a mistake.

Ssiscool

Corrected entry: When McClane and Farrell are stealing the BMW 5-series in Washington DC, Farrel hits the cars bumper with a trash can in order to deploy the airbags and prevent McClane from disabling the vehicle. Airbags do not deploy if vehicles are hit on the bumper with small objects, only if the vehicle is hit with sufficient force to trigger the airbag, usually by another vehicle or a large stationary object.

Razvaluha

Correction: This is a valid mistake but your reasoning is incorrect. There are compression sensors across the bumper and if sufficient pressure is applied the airbags will deploy BUT ONLY if there is also sufficient deceleration detected by the ACU (to prevent such unnecessary deployment). As the car is stationary it is not possible to set off the airbags in this manner. http://en.wikipedia.org/wiki/Air_bag#Triggering_conditions.

Ssiscool