Originally Posted by JJeffrey

The reservation doesn't need to be in your name, all that matters is that your card is used at a qualifying property. So this depends entirely on the specific hotel and front desk staff and policies, etc.

One option is this: book the reservation in your SO's name, on the check-in day call the front desk and tell them you want to surprise your SO by picking up the tab for her stay and give them your card #. Shouldn't be an issue.