Zoe O'Connell at Complicity provides a summary of the argument against this move - "We can hardly defend our position on being against ID Cards if we give in to this. We’re basically admitting that the database state is required to ensure our security" - and links to some other posts on the subject.
There is an online petition, which I have already signed.
Liberal Democrat Voice has a reply to critics of this move from Andrew Wiseman, the chair of Federal Conference Committee. In it he manages to display disingenuity:
I have been alarmed to see some comments which seem to suggest that we should not have to take security considerations into account at alland candour:
Our insurers want to know that we act on police advice and if we do not we run the risk of invalidating our insurance. Without the necessary insurance no conference venue will accept our booking.in the course of one paragraph.