I don't think it's "rule of law" here, but information parity.
How you become sure you have as much information about the subject as the person you're dealing with (i.e., whether that's because it is required by law and you expect to have some recourse if it's violated, or because you are confident that you've had access to the relevant information for some other reason) isn't really important.
How you become sure you have as much information about the subject as the person you're dealing with (i.e., whether that's because it is required by law and you expect to have some recourse if it's violated, or because you are confident that you've had access to the relevant information for some other reason) isn't really important.