i tested over and over, and was unable to find any bugs with it as is. it would be nice to have a way to set the option in the channel to notice the guest user about their nick, then have the channel auto ban them and kick them from the channel.
having a setting maybe that allows you to do something like
/msg chanserv set #channel guestdeny on {Guest Nick(s) To Block}
/msg chanserv set #channel guestdeny off
this way each channel could decide on their own if they wanted guest nicks to be blocked
some users actually use nicks like Guest12345 and some people like myself find that annoying and would like to be able to block them as well instead of just the networks guest nick that is preset.