Defective seatbelt Lawsuits have been brought against vehicles designers who equipped the vehicle with inadequate non-integrated shoulder harness and lap belts. When these are not properly integrated (thus kept in two separate parts) the shoulder harness won't automatically engage. Thus, when an occupant shuts the door, the lap belt has to be manually secured.
Seems like a "neat" feature -- but it really serves no purpose except that it can harm the passenger. For example, if a young child were sitting in the front passenger seat, manufacturers know that occupants – especially youngsters – were prone to ignore or to forget about the manual lap belt. Thus, they mistakenly rely on the shoulder harness alone.
This gives the passenger a false sense of security. As a result, upon a front-end collision, the occupant "submarines" under the shoulder harness, which can result in fatal neck injuries.
When an integrated seat belt system is used, there is no problem of ignoring or forgetting about the manual lap belt.