Going to Mandalay Bay next week (Weds - Sunday) and planning on trying the $20 sandwich trick. It seems from what I have read on this forum and others that, if an upgrade is given, it is usually from MB to the Delano. That would be great, but my wife is concerned that if we stay at Delano, she will not be able to use the spa at MB. (Yes, I know that Delano also has a spa, but MB's spa is her favorite on the strip.) Does anyone know whether guests of Delano can also use the spa at MB? And, if not, is it even worth it to try the $20 sandwich?