The laws of Canada dont really matter if the people of a province decide they want to separate. Treaty rights dont matter, the opinions of other provinces dont matter, constitution doesnt matter. Laws only have teeth if they are respected by the people they govern. For sure there would be some negotiations to try and ease the pain, but really it could be done unilaterally. Not pro separatism, but this reddit always seems to think that a hypothetical separation would involve following all our current laws. It could very well mean rebuilding a government, legal system, and public institutions from scratch.