I would hope that they give you a hard time. You seem to be attempting to get Plat cardmemeber privileges for both of you in exchange for the annual fee of a single cardholder.

IANAL but have you thought about who would be responsible for the AmEx bill in case of divorce and also what effect this could have on one's credit score. What if one of you later wants to get an additional signup welcome bonus from AmEx? Her card but issued in your name? It could turn into a mess. I'm surprised that AmEx permits this.