This would be true if your offer was negotiated with a distant bureaucratic committee (or board), but most of the time, regardless of who they represent, you're just dealing with people.
Many companies, particularly the larger organizations, have pretty strict boundaries though. Case in point: in a large corporation we tried recruiting an incredibly talented developer, but because of company rules, we couldn't offer him what he asked for despite us thinking he was definitely worth it (and really, it wasn't outlandish in any way) but HR would never let it fly because rules. His problem then, I think, was that he mentioned what he'd earned elsewhere, so some policy dictated we couldn't offer more than 20% than that, or whatever. Stupid, silly policy, and just goes to show you should never divulge information the other party just isn't privy to. (I've never told recruiters what I earned before, that's not their business.)
