This, I don't know about counseling, but just think it through. First a spring has to break, that certainly could happen. As many have mentioned, most likely to happen when the door is at the bottom of travel, it doesn't have far to fall, and I assume your girlfriend isn't slithering like a snake under the 18" it is open.
Probably worst case a spring snaps halfway up, it could slam back down, once again, is your girlfriend limboing under the door when it is halfway up? All the way up, probably pretty well balanced and not likely to slam down.
She gets impatient with her car, drives under it when opening before all the way open, spring breaks, unless she drives a motorcycle or convertible I am sure the car can take the impact, if any, personally for a single stall residential garage door, even a single piece, the opener holds it.
Tell her not to walk under it when opening, get an opener appropriate for the door, forget about it.