Thanks for all the replies!

We're actually more interested in the nights, as opposed to the points (which we seldom use anyways). If she were to make her own account, is there any way we can combine our nights? I'm assuming not...

FWIW, a close friend runs a business where he often is entertaining guests from abroad and books multiple guests into multiple rooms at a hotel (he himself does not stay, since he is local). He's thus been able to rocket up elite status quickly. So based on what people are saying here, this technically isn't allowed?