As I understood 802.11k, the AP won't inform, the device, about the neighboring APs that are not visible wirelessly to itself, the AP. The 802.11k should inform all wireless networks, that belong to the same local network, connected through either cable or wifi. This way the device can just make a fast check for the rssi, of only these networks, to build its own point of view. What matters for the device is which wireless networks are neighboring itself, doesn't really mater what is neighboring the AP wireslessly, as long as these neighbors are in the same subnetwork, which means the device will keep the same IP after the switch. The time when the device needs that information is when it's already far from the AP, so the AP's point of view is irrelevant. I hope I have got the presentation wrong. And while switching/roaming, the 802.11r must not inform the OS that it lost connection and is reconnecting, to not let the OS inform it's applications of a loss of connection (I don't know whether it's already implemented like that or not or if it's vendor specific).
