I don't recommend making your eggdrop ban-kick every nick that has same nick and ident.
The reason is simple, those spammers have so many ips to use and DALnet's ban list is limited to 100 ips. It will make your eggdrop go crazy as they join successively and it would fill up the ban list in no time.
Those spammers are usually auto-killed by DALnet services a few seconds after they connect.