Buick 2006 LaCrosse Owner's Manual page 36

Q:
What if a child is wearing a lap-shoulder belt,
but the child is so small that the shoulder belt
is very close to the child's face or neck?
A:
If the child is sitting in a seat next to a window,
move the child toward the center of the vehicle.
Also see Rear Safety Belt Comfort Guides on
page 1-25. If the child is sitting in the center rear
seat passenger position, move the child toward the
safety belt buckle. In either case, be sure that
the shoulder belt still is on the child's shoulder, so
that in a crash the child's upper body would
have the restraint the belts provide.
1-30
CAUTION:
{
Never do this.
Here a child is sitting in a seat that has a
lap-shoulder belt, but the shoulder part is
behind the child. If the child wears the belt in
this way, in a crash the child might slide under
the belt. The belt's force would then be applied
right on the child's abdomen. That could cause
serious or fatal injuries.