computer says "no"
As with most IT systems, it's not just the database or the ID cards that are the problem (although they are a pretty big problem), it's the faith people put in what the computers tell them.
Little Britain got it so right with the "The computer says 'no' " sketches.
The people are an integral part of any system. What is Jane actually going to be able to do when confronted with John denying her access to services (or liberty) based on what the computer 'says'. John's operational 'procedures' won't allow him to listen to any protests that 'the computer' might just be wrong. Jane will be asking "can I go home now?" and John's answer will be "the computer says 'no' ".
I have absolutely no faith in any government's ability to put in place working procedures across multiple agencies to ensure that data quality/accuracy problems can be dealt with rapidly, fairly and accurately. They're going to concentrate on the sexy technology and conveniently forget about the processes and checks/balances to wrap around it.