Saturn 2004 Ion - Manual (Page 69)

Keys
{ CAUTION:
Leaving children in a vehicle with the ignition
key is dangerous for many reasons. They could
operate the power windows or other controls or
even make the vehicle move. The children or
others could be badly injured or even killed.
Do not leave the keys in a vehicle with children.
One key works the ignition and all of the lock cylinders
on the vehicle.
2-3