Don't know if they change the colors, but last time I stayed at an Author's Suite (the Coward suite) and the robes were grey silk. Once a good friend of mine got married there to a well-connected Thai woman, and he blocked off the entire Author's Wing for the weekend festivities, including the rooms and the common areas. We'd stay up all hours of the night on the verandah drinking and smoking cigars, catered hand and foot by an army of staffers. I truly felt like a colonial invader, great fun. No great fun, however, for all the remaining guests (and perhaps even non-guests!) who wanted to have tea or even visit the Author's Lounge, the whole building was off-limits to non-revelers. Tough!