See also:

CARGO AREA COVER
Nothing should be carried on top of the luggage cover. Loose materials could result in injury to vehicle occupants during sudden braking. ...

Care of seat belts
Seat belt systems should never be disassembled or modified. In addition, care should be taken to assure that seat belts and belt hardware are not damaged by seat hinges, doors or other abuse. WAR ...

One Person Per Belt
Two people (including children) should never attempt to use a single seat belt. This could increase the severity of injuries in case of an accident. ...