Harnessing and Blankets or Bunting Bags - Bundling infants into large bunting bags or layers of warm blankets before harnessing them in their seats makes correct positioning of shoulder and crotch straps impossible. A harness fitted loosely over layers of blankets or secured around a child's waist will not keep the child secured in the seat. If extra warmth is required, place the blankets over the harnessed baby. Neglecting to Harness - This could allow the child to be thrown out of the child restraint. It is a very hazardous object for an unharnessed child to be thrown against.
Some car seats have shields which are safety features.
Check the instructions to see if a harness is also required. Positioning - Don't face an infant in the forward facing position too soon. Infant seats are not designed to face forward at all and will not protect an infant in that position. Keep a child in a rear-facing position until it is able to pull itself to a standing position or is sitting very well unattended. If your newborn is quickly outgrowing the manufacturer's suggested height and weight limits for the infant seat, prior to being ready to be turned around, you may find a convertible seat will provide extra room and time in the rear-facing position.