Canada also uses a one party rule. As long as one party knows the conversation is being recorded. If you are part of the conversation, you can record, without anyone else knowing.
Yup- just with a caveat being that, if it’s for law enforcement purposes, you need a warrant, or else the evidence gets thrown out. Usually we use One Party warrants with an undercover officer or police agent (a confidential informant who is actually directed by police to take certain actions).
But yeah, generally speaking, in Canada, any participant to a private communication can legally record it without telling the others.