If they'll replace it for scratches then who needs insurance
You could have gotten the scratches from something in your pocket or some dust particles in your hand or in the cloth you wiped the screen with. I wear glasses and all I do with them is wear them or put them on the night table when I sleep (i.e., I take good care of them), but they get scratches over time. I think it is very important to make sure that your hands and and the cloth you use to clean the screen are pretty clean.