CAN THE POLICE OBTAIN YOUR INTERNET SUBSCRIBER INFORMATION WITHOUT A WARRANT? Yes they can!

Although it is a search which is not lawfully authorized that constitutes an unreasonable search that violates your privacy interests, the information obtained as a result of the search will not be excluded in a trial as its admission will not bring the administration of justice into disrepute.

 

http://www.canlii.org/en/ca/scc/doc/2014/2014scc43/2014scc43.html

Thanks to Cheryl Sereny for this!