Since the movie was so low budget, in the scene where Jason Patric is running around with a photograph, the people he was asking were passers-by, not actors. So the people would genuinely not know who he was talking about.
Tom Cruise was so impressed after seeing the movie that he took on the role of executive producer, and made sure the movie got a wider release than originally planned. He also convinced director Joe Carnahan to take the director's chair for Cruise's upcoming Mission: Impossible III (2006). However, not long after production started, Carnahan left the set due to creative differences with Cruise.
Ray Liotta gained 25 lbs. for the role by eating foods heavy in carbohydrates. Before he would shoot for the day, he prepared by eating Chinese food because the soy in the food helps to retain water and give him that "puffy" look. He also wore a fat suit under his clothes at all times as well as prosthetic skin under his eyes to give him an aged baggy look.
Both Ray Liotta and Jason Patric participated in the film for nearly no money. In fact, at one point during production the cast and crew's paychecks weren't coming through due to legal and budgetary issues, so Liotta and Patric worked for free because they liked writer/director Joe Carnahan and didn't want to see his career ruined by the shutting down of his movie.
The run-down auto parts shop where the final scenes of the film take place was an actual abandoned chop shop that the filmmakers located in Toronto. Jason Patric claimed that it was one of the most miserable, uncomfortable environments he'd ever filmed in.