Artie Decker: I'm not going!
Diane Decker: You're going!
Artie Decker: That's what I meant.
Artie Decker: I'm awkward around those kids. I don't think they like me.
Artie Decker: OK, hop out.
Barker Simmons: I'm still buckled in.
Artie Decker: Oh, boy. This is harder than one of your grandma's bras.
Barker Simmons: It's not rocket science.
Mr. Cheng: Just Pan Asian!
Artie Decker: What's that?
Mr. Cheng: No MSG, No gluten, No sodium, just healthy food!
Artie Decker: I'm drooling already! [Others start walking away.] How do you ruin Chinese food?
Harper Simmons: Mom, you lied to me! Yogurt is not like ice-cream!
Diane Decker: If they don't see you enough, they have to know you better before they don't like you.
Answer: It's demonstrated throughout the film that Artie struggles with the modern way of doing things. This may extend to modern car seat belts with their five point harness systems. That and the fact they're already late for school and holding up the traffic makes it a stressful situation for Artie and it was probably easier (and to add comedy) for Artie just to rip the seat out with the boy still in it.
Neil Jones