I find this idea genuinely intriguing. If such an idea were to work, it would need a clear-cut definition dividing the two types of information about a person (

I find this idea genuinely intriguing. If such an idea were to work, it would need a clear-cut definition dividing the two types of information about a person (since we're talking in a legal context here, and you'd need to be able to defend yourself if Bob argues you shouldn't have a given piece of information that you have). What if I lent you money and you never repaid me -- could you legally prevent me from telling anyone about it, by virtue of it being private information about you? If you think that's unreasonable, isn't that more or less the basis of your credit score?