I think the balancing act, so to speak, is to put the emphasis on suspicious transactions, and those are fairly clearly outlined. Even then, FINTRAC holds that information very closely guarded, and only discloses key identifiers and publicly available information. If a law enforcement agency wants additional information, they must go to court and actually get a court order requiring FINTRAC to provide additional information. So there is the filter of a court process to ensure that anyone's privacy is breached only when there is good and sufficient grounds to do so.
Once a person has been convicted, of course, that's a different issue, and I don't think you're really asking about that.