I know we had some collegians who were leery of giving out their ssn. I guess this is preferable to back in the day when we splashed it all over every postcard we filled out at college fairs and didn't blink an eye.
If someone close to her had their identity stolen it's understandable she'd be more than a little cautious. The best thing for her to do would be to ask her NM educator to call the national office for her so they can explain how the number will be used and the security measures they take.