Greg picks his grandfather up at his home in Canada before driving over twelve hours back to New York for Thanksgiving dinner with the Roy family. In late November, this would mean either starting the drive before dawn, or arriving well after dark, however the scenes both before and after the drive are shown to be in full daylight.
Tom did not need to even tell Greg that the documents he wants him to shred are evidence about crime. He could have simply told him that it was all about data protection and privacy regulations or that he wants a family member to be there and make sure no menial laborers grabbed any papers to sell them to competitors.