GMC C series 2002 Owner's Manual page 23

Q:
What's wrong with this?
A:
The shoulder belt is too loose. It won't give nearly
as much protection this way.
1-16
CAUTION:
You can be seriously hurt if your shoulder belt is
too loose. In a crash, you would move forward
too much, which could increase injury. The
shoulder belt should fit against your body. Don't
allow more than 1 inch (25 mm) of slack.