From my experience, many (most?) properties I've stayed at over the past few years at least in North America have "Starwood Preferred Guest Floors" but having traveled with non-Plat colleagues, even when I stay on those floors with non-Plats, I have access to the Club but they don't. I don't think being assigned a room to the SPG floor automatically entitles the guest to Club access. Come to think of it, there have been instances where non-SPG member colleagues have been either on the SPG or even Club floor and while I received club access, they didn't.

I've stayed at that property before and, in fact, have been assigned a room on a non-SPG floor but have nevertheless received Club access because of Plat status.