satori:

When you ran your numbers, what assumptions did you make about credit card usage? Did you assume that the top-tier guest uses the appropriate program credit card for their stays, but not other spending? Or did you also assume that the top-tier member uses the appropriate card for $X dollars/month of non-hotel spending.

The reason I ask is that it appears from reading FT that nearly all active Starwood folks use the SPG Amex as their primary card. HH and MR top-tiers are more mixed: most use the appropriate card for their stays, but many use other cards for their other non-hotel spending.