There is proof that RCMP have the decryption key to BBM, Pin messages and other ways to intercept "secure" BlackBerry information???
https://news.vice.com/article/exclus...yption-key-how
More here from CBC.
RCMP can spy on your cellphone, court records reveal - Technology & Science - CBC News
It seems it is well within the police rights and capability to monitor phone usage, which includes BBM without any difficulty.