Perhaps she took along some filled gas cans. Who knows what was going on in her mind?
Unlikely. If her car got 30 mph thats about 67 gal for the round trip. Say her tank held 15 that's 52 gal deficit or 11 filled 5 gal cans (3 gal margin). I don't think I could fit that many in my car plus the report would have mentioned something that weird. My guess is she just lost it.
mph = mpg