When the condition presents itself you might try wiggling the key or perhaps moving a little more clockwise or counterclockwise to see if it makes a difference. There is a bit of a history with these cars having ignition switch problems (I replaced mine at about 150,000). Does your friend carry a number of keys on her keyring? Several people have suggested that a heavy keyring increases the likihood of a switch failing. It's as simple as unpluging the connector from the switch and removing two screws to change it out but of course its location under the dash requires determination and a young neck that can quickly recover from being twisted into unnatural positions.

Randy