There appears to be a solid evidence trail of different interpretation of SPG guidelines (T&C, if you must) for a number of Latin American properties. I am keenly aware that this group of hotels is overseen by a separate *wood division, much like Europe or Asia is; nevertheless, consistent issues with upgrades at hotels like the MEX S Maria Isabel gets to be very frustrating.

My position has been this: as long as there is sellable space available on Club Floors or Towers Levels (or whatever -- corner rooms, etc), they should be assigned (based on availability) at check in to Plat members. The S Maria Isabel's argument that the Towers Lounge would be overrun if they permitted Plat members access is a faulty one if they abided by the formula I outline above.

I.E. -- if we have empty Towers rooms available when you check in, then you get one. If we don't, then sorry --- and you won't get access to the Towers Lounge on this stay. Surely that would be a better solution -- -and the hotel has the guarantee of only having the lounge opened to guests staying on the Towers/Club floors.

Even this, admittedly, is outside of how I read the SPG T&C, but it is clearly an improvement over the Maria Isabel solution of allowing NO ONE access to the lounge except paying Towers Guests.

This has been just about the only area where Starwood has let me down. They appear to be aware of this skirting of the benefits on the part of the hotel (and a quick search will bring up scads of statements like the OP's above where staff members of the Maria Isabel are not shy about advising guests that they play by a different set of rules and are exempt from some of the ones we're all used to.) I wish this would get resolved or at least competently addressed.