Consequences must be consistent. If the child throws his food tomorrow or the day after, the same result must occur. Inconsistent consequences confuses and frightens children. They cannot predict what their parents will do. Make sure the consequences make sense and are not more severe than the misbehavior.
Some threats are unreasonable.
You took the car without my permission. If they follow through with these threats, parents would be over reacting. If they fail to respond, parents would lose their children's respect. Respond in private. Embarrassing a child in front of others creates unnecessary anger and undermines dignity and self-esteem.