Excerpt from Mazda: "When driving at low speeds (approximately 4 - 30 km/h) a laser sensor mounted on the windsheild senses the car in front. If the system detects a risk of collision, it prepares the brake system to be ready to deliver maximum stopping power when the driver brakes. If the driver does not take evasive action such as braking or steering, the system simultaneously applies the brakes and reduces engine output, with the aim of avoiding the collision or reducing the severity of impact."
I don't think the sensor for the SCBS is housed within the front emblem, it should be the windshield. Also I'd imagine it "see's" objects based on many factors/conditions so having foam padding on a wall may throw off the readings from the sensor because it recognizes density. insulation padding is probably not dense enough for the sensor to get a good reading, something more solid would probably provide more consistent results.