On check-in at Club Regina Los Cabos, we debated about using our Starwood AM EX for incidentals and charging to the room. We were unsure if the charges would be listed on our account as "Westin" (since it's a Raintree property) therefore earning the additional bonus SPG points on the card. We chose to give them a different card with a better foreign transaction fee.

I just received our statement for that card and it is listed as "Westin Hotels Los Cabos."

I wish I had known prior to our visit so I thought I would pass the info along.