Is this a normal financial aid requirement?

Showing the original card proves that the social security number is yours, but I don't think there is any risk other than the risk of losing the card if you carry it around.

A school can request any documentation it deems necessary to resolve conflicting information. If there is an issue with your social security number on the FAFSA, many schools will require that you bring in the original so they have proof that you aren't providing a copy of a card that has been tampered with. While they may not suspect you in particular of doing this, the school may have a policy of always requiring an original whenever there is a question about a ssn. It may be a nuisance, but take comfort in the fact that a school that does this treats the problem of identity theft seriously. One that settles for a student just telling them the number, or takes a copy, is not taking as much care as they could to safeguard your personal information.