Not legally, no. However, it is quite likely that you could sneak her by the system--just make sure she picks the tickets up from an automated machine (if she picks them up from an agent, the agent may ask for the AAA card).
Once she has the tickets and boards the train, it's EXTREMELY unlikely (as in, nobody around here has EVER been asked) that she'll be asked by the conductor to show the AAA card. I've traveled many, many segments on Amtrak with my Student Advantage card discount, and I've NEVER been asked to show the card itself. (Conductors simply don't care.)
Not that I'm encouraging you to beat the system...
Programs: Peon in many programs - but finally Select in AGR
Most conductors only care if you have a ticket to go from "A" to "B" - not how much you paid. (Many don't know or care what AAA or V454 or H570 or ... is!) As long as you hold a ticket, they will (normally) take it without question.
I have travelled many time on the AAA fare, many times on numerous promo codes and a few times with the handicapped discount. I have NEVER been asked by the conductor for roof.
The only time I've been questioned about my ticket has been when I used a credit card to buy my ticket, and the ticket was not signed. (It need to be signed.) The conductor just gave me his pen, and continued to collect the next few tickets - and then came back to collect my signed ticket!