Chevrolet 2003 Venture Owner's Manual page 63

Never do this.
Here two children are wearing the same belt.
The belt can't properly spread the impact
forces. In a crash, the two children can be
crushed together and seriously injured. A belt
must be used by only one person at
a
time.
0:
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:
Move the child toward the center of the vehicle, but
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 that belts provide. If
the child is sitting in a rear seat outside position,
see Rear Safety Belt Comfort Guides for Children
and Small Adults on page 1-52. If the child is
so small that the shoulder belt is still very close to
the child's face
or
neck, you might want to place
the child in a seat that has a lap belt, if your vehicle
has one.
1-56