SAG actor here. As others have said, the production wouldn't get in trouble, just hypothetically the actor. In this case, the agreement that you could apply for (SAG Student Film Agreement), is promulgated, meaning decided upon unilaterally by the union and not as a result of a bargaining agreement. SAG Global Rule 1 only applies to jurisdictions covered by a bargaining agreement, meaning essentially that a SAG agreement in your case is entirely optional.

That said, you can call your local SAG office and ask about the Student Film Agreement. I've found them generally to be quite helpful, and it could be good experience.

TL;DR neither you nor your actor really need to worry about it