Terrorism is a reality of modern life, but it is only one of many threats to our safety and security. True security is only an illusion, and ID checks aren't going to stop terrorists. People have argued that privacy is essential for democracy and civil justice. In a democracy, privacy protects individuals from coercion. For this reason, the 'secret ballot' is guaranteed.
Privacy is a necessary ingredient for effective civil justice.
It helps protect against prejudice and re-victimization. Few argue against the withholding of criminal records of minorities and the withholding of the identities of rape victims. In these cases, privacy protects. But in the instance of an airline, electronic database, genetic database, or any of the other technology related privacy infringement issues, the above arguments may be unsatisfactory. Some would suggest that privacy infringement is necessary to maintain civil justice in the latter instance.