I don't know if this was the case with Starwood, but some hotel chain uses caller ID and links that info with a frequent guest program account number for that brand's customers. So a call's phone number derived from caller ID links account number, email address and the works so that the CSR knows who they are speaking to before the customer may even open their mouth. Such systems pose a security risk in that people calling from certain non-exclusive phones (hotel phones, conference room phones, pay phones, resold prepaid SIM-using mobile phones, etc.) could easily have their info stolen by "social engineering" miscreants who could also readily misuse the info/account.

Perhaps Starwood Lurker could comment about whether or not Starwood uses such a caller-ID-based system or has considered such at some point.