Well, I can speak to some elements of your question.
In the case of a refusal or a revocation, the decision is communicated back to the client in the form a revocation or refusal notice. The refusal notice or the revocation notice expressly lists the part of the Firearms Act and/or the Criminal Code that the CFO believes the individual is in violation of.
It isn't simply revoked or refused. The individual is given a very full accounting of the grounds on which the CFO has made that decision. They do get the opportunity to see the information on which the CFO made the determination.