7th circuit ruling: police search of a cell phone for its number, without a warrant, is permissible

"The U.S. Court of Appeals for the Seventh Circuit ruled today that a police search of a cell phone for its number, without a warrant, is permissible. Police had retrieved the phone in question from the scene of a drug sale and later used it to subpoena phone records.

Judge Richard Posner, writing for the panel, used the diary analogy:

If police are entitled to open a pocket diary to copy the owner's address, they should be entitled to turn on a cell phone to learn its number. If allowed to leaf through a pocket address book, as they are, they should be entitled to read the address book in a cell phone. If forbidden to peruse love letters recognized as such found wedged between the pages of the address book, they should be forbidden to read love letters in the files of a cell phone."

rest at 

http://blogs.wsj.com/law/2012/02/29/the-daily-writing-sample-cell-phones-and-diaries/