Gratuitous ARP

Hi,

I am trying to find out why gratuitous ARP isn't implemented for IPv4
duplicate address detection, though a comment is present in the
arp.c that it was added. Was it removed for any reason ? I went
through netdev archives and found some threads relating to this, but
no comments were there on why this feature is absent or removed.
Could it be to avoid a flood arp attack ? If so, any reason why it cannot
be implemented under a configuration param ?

I would appreciate if someone can throw any light on this.

Thanks,

- KK