The "bump key" technique used by Russell Crowe's character does actually work as portrayed on older and cheaper (non-antibump) cylinder locks. However, the car lock tennis ball technique has been busted as a myth on MythBusters: Viewers' Special (2007)
Mark Isham, director Paul Haggis's regular collaborator, did not compose the score to this film, due to their falling out over Haggis's highly publicized decision to leave the Church of Scientology, of which Isham is still a member.
Elizabeth Banks met with prisoners and guards to get a better impression of what life in jail might be like. She was incarcerated in a cell for as long as she could tolerate - which amounted to about five minutes.
Paul Haggis selected Pittsburgh as the main location as he wanted one that was relatively close to the Canadian border, figuring that would be a logical destination for someone breaking their wife out of prison. He also wanted the location to be one less cinematically familiar than New York City or Chicago.
Paul Haggis was looking for an alternative film to make, when his planned biopic of Martin Luther King fell apart due to budget problems. That was when he chanced upon the French film Pour Elle (2008).
Russell Crowe was Paul Haggis' first choice for the lead. At the time, Crowe was working on Robin Hood (2010), and was tired of the film's lengthy production, so wasn't initially keen about jumping into another film. The script convinced him otherwise.
The actual place, although never officially disclosed, where John is taking Lara and Luke, is Carácas, Venezuela. The destination, Carácas, can be seen on the airline ticket when John's father looks at them. The destination is disclosed when they are on the plane and you can hear an announcement on the PA: "Flight time to Carácas, Venezuela this evening is 5 hours and 32 minutes". Also, in the next scene, John's father is shown clearly looking for Venezuela in a World Atlas.