The best solution I can come up with at the moment is to add "-%ircnick" to the requested dir on !reqadd.
I don't consider this as a really nice solution and will most probably disable those command by default. If you really want something, you can at least login
They will most probably be available in ioB2 anyway (but disabled as I said) since they don't really eat cpu or bw.
WarC: There's an option to specify nuker username and group on NUKE, what about the same one on REQUEST ? I know irc nicknames aren't the sames as usernames ; I would use usernames on the bot, not in channel.