GMC 1997 Safari Owner's Manual page 88

Theft
Parking at Night
Vehicle theft is big business, especially in some cities.
Although your vehicle has a number of theft-deterrent
features, we know that nothing we put on it can make
it impossible to steal. However, there are ways you
can help.
Key in the Ignition
If you leave your vehicle with the keys inside, it's an
easy target for joy riders or professional thieves -- so
don't do it.
When you park your vehicle and open the driver's
door, you'll hear a chime reminding you to remove your
key from the ignition and take it with you. Always do
this. Your steering wheel will be locked, and so will
your ignition and transmission. And remember to lock
the doors.
Park in a lighted spot, close all windows and lock your
vehicle. Remember to keep your valuables out of sight.
Put them in a storage area, or take them with you.
Parking Lots
If you park in a lot where someone will be watching
your vehicle, it's best to lock it up and take your key.
But what if you have to leave your key? What if you
have to leave something valuable in your vehicle?
0
Put your valuables in a storage area, like your
glove box.
0
Lock all the doors except the driver's.
0
Then take the door key and remote keyless entry
transmitter with you.