When Porter picks up Kaitlyn at school, she is wearing ankle boots with her short school uniform skirt. In the next scene, just arriving at her home, she is still wearing the same uniform skirt but now with knee high socks and loafers.
When we first see the name of the wife's doctor it is spelled Klien, the second time it is spelled Klein.
Though the movie is set in the United States, every time one of the characters makes a telephone call the ring tone heard is the European style two-rings at a time type tone.
After Ed remotely crashes Mike's car, his video screens go dead and show an analog static pattern. The cameras in Ed's car would clearly have to be digital so his screen should have just gone black.
When Ed drives by the school to persuade Kaitlyn to get into his car, double-yellow lines on the side of the road are clearly visible. However, double-yellow lines aren't on the sides of American roads, but are used to restrict parking in Britain and Ireland.
Mike is arrested by the city of Baltimore, which is 50 miles away from where he lives in DC.