I'm not averse to it. I guess I'm playing devil's advocate. An item of furniture is not in itself electrical equipment no matter if it's made of metal. The electrical equipment is the socket, which is to be attached to the furniture. Any cables supplying the socket would be insulated and sheathed. If you fixed a socket to a cable tray, would you then have to earth the cable tray?
Or if a socket was to be affixed to a stainless steel splashback, would you have to earth the splashback? A metal suspended ceiling light fitting is in direct contact with a metal ceiling grid, would you have to earth the grid?
And as an aside, the term "bonded" was used earlier, which is not the correct term for this sort of situation.
Like I said, I'm not averse to the furniture being earthed, but I also think that it's not an automatic assumption that it has to be, based on the definitions found in BS7671. When referring to equipment that could become live under fault conditions, the definition of such equipment does not include furniture. Unless of course the manufacturer of said furniture has designed it in such a way that it is part of the electrical equipment, and explicitly provides an earthing point to facilitate the connection to earth.