Because another airline would be able to avoid a surface-to-air missile?
Your friend is a fool. If she's flying from Oz to KL ask her to point out any dangerous airspace along the route.
She meant to say metres. These planes cruise between 35,000 - 40,000 feet. People skydive about 10,000 - 12,000 feet.
It looks like this was an accident and the plane was mistaken for a Ukrainian jet.