I'm not sure what the official policy is concerning in-house amenities, perhaps someone know for sure:

I just completed a stay at the Arizona Biltmore (Waldorf Astoria), and although we received Salvatore Ferragamo hair products, the bar soaps were definitely not Ferragamo; some generic wrapped pill-pressed rounds that were not luxurious IMHO.

I seem to only encounter this at WA properties, although, most do supply all Ferragamo products. So are they not required to offer Ferragamo products exclusively I would tend to think there is some sort of marketing agreement between WA and Ferragamo, but maybe not. Wonder if Ferragamo is cool with WA hawking other designer's brands.