A solution in pacman, getting rid of user adding in .install script, can allow security like asking user to confirm creation of group and user.
This would be a secure way of doing thing, and users/admin would be aware of new user/group. And like glenn, I'm wondering how package can add or remove daemon. These are users set, and when are ok, need no worries. If package add/remove them, it's unexpected problem coming to the user.
