On rear - facing car seats the strap needs to go through the child's legs. (howtoadult.com)
Secure car seat straps are helpful, but the rest of the car seat should fit appropriately as well to keep your baby as safe as possible. (thetoddle.com)
Your little one will not feel the effects of a tight car seat strap, but they would feel the result of one that was too loose in the event of an accident. (live.happybottomus.com)