In the Supreme Court of Canada’s case of R v. Telus, a 5-2 decision was made that law enforcement need wiretap authorization to intercept text (SMS) messages. No longer will a search warrant suffice. You can read the Canadian Civil Liberties factum [pdf], as they intervened in the case.
A few interesting quotes:
“over the last few years, Telus has received tens of thousands of search warrants, production orders and interception authorizations from police, requiring them to hand over customer information and communications” – CCLA
“Electronic surveillance has been described as the greatest leveler of human privacy ever known” R. vs Commissio