While I've had that as well, I've also had occasions where the hotel staff replies "oh yeah, to get the cheaper rates you'll have to go through <agent-site-with

While I've had that as well, I've also had occasions where the hotel staff replies "oh yeah, to get the cheaper rates you'll have to go through <agent-site-with-lower-list-price>" when calling them, or even trying to extend an existing reservation at the desk. Norms do seem to vary between regions and countries.