ARP flush

Hello folks,

Need help..

I want to know the background/history of doing the neighbor flush for the interface Mac address change.

void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev)
{
write_lock_bh(&tbl->lock);
neigh_flush_dev(tbl, dev, false); <<<
write_unlock_bh(&tbl->lock);
}

What would be the implications if we don't flush the neighbors for interface Mac address change event.

Thanks,
Nagendra.