I believe I do have a timeline of events that you might find revelatory.
The Wilkinson family pull Christmas crackers around the table, starting with Vanessa and Uncle Newt. Vanessa wins and immediately takes the hat from inside and rips it up.
She also gets a small plastic cowboy from the cracker, which she gives to her grandson, Benji. Benji is warned not to snatch by his mother, Hilla, who reminds him that “Level 3” behaviour is expected.
Jerry says “onwards and upwards” and nominates Deborah to pull the next cracker.
Deborah chooses to pull her cracker with her grandfather, Walter. Vanessa indicates to Walter that his cracker is on his side plate. Deborah wins, but questions if she has to rip up her hat. She asks if that tradition comes from them being a bit Jewish.
Hilla tells her that lighting the candles is because they are a bit Jewish, but that the hat ripping comes from the Wilkinson side. It transpires that the tradition dates back at least as far as Uncle Newt’s childhood.
Uncle Newt prepares to tell the story of why the family rip the hats, but he is interrupted by a kitchen timer. Hilla bustles out of the room to fetch the pudding, enlisting help from Myra.