Visible crew/equipment: Early in the the film, after the attack in a shot with police tape in view, you can see a camera on a dolly along with the focus puller in the left side of the shot (wide screen version). (00:11:55)
Continuity mistake: When the three IRA members go to Kevin's house, he shoots one through the glass in the door. When he is leaving the house a short time later, the broken glass has a different shape. (00:18:15)
Continuity mistake: After Cathy Ryan's car's back window is shot out, she swerves to the right toward a black Jeep with license plate 934-072, but the angle changes and when the car hits the Jeep its plate is THA-1L3. (00:50:30)
Answer: The movie never clearly says. It was some event that required tickets, as the mom runs back into the house to get them. And it was something Sally really wanted to go to, but it is never clear what the event was.