How Do You Know if You Have a Reasonable Expectation of Privacy?

No court since then has suggested that the authority to conduct pen registers without a probable cause warrant was limited by the number of days. If you don't have a reasonable expectation of privacy in your diale telephone numbers, then you can't have a reason expectation of privacy, because other people's dial telephone numbers are being corrected. I think that this a case which fits squarely within sort of the core of the established constitutional doctrines. There is no way, i think, that you can decide this case without fundamentally undercutting established law and creating lots of chaos and confusion for law enforcement and other agencies who relied on that established for a long time.