There is no point, and it populates the cache with entries we don't
need. Local containers will still need to issue an ARP request when
they first talk to an IP corresponding to the MAC, so we learn about
the MAC at that point, just as normally happens.
We don't need. Multicast addresses never appear as sources and hence
never end up in the peer_cache. And the router always broadcasts
frames with destination addresses that aren't in the peer cache.
Matthias Radestock