Sure, but it'd be extremely hard to prove if that bias has penetrated that firewall or if it hasn't. I think the reason it has (mostly) worked for journalistic

Sure, but it'd be extremely hard to prove if that bias has penetrated that firewall or if it hasn't. I think the reason it has (mostly) worked for journalistic institutions is that it is a profession that are taught a set of ethics as a part of their education and it has a history of adhering to those ethics. Proving a non-bias for what is your own actual financial interest seems almost impossible. I'm not saying it can't be done ever, but I would not want to have to argue either side of that. I said this in a comment below but I think it is relevant here too: Restricting speech is in general hard, what would be much easier is to require clear and obvious disclosure. Since journalistic ethics already requires that it should only require changes for dishonest actors. EDIT: To clarify: those firewalls are often in the journalistic institutions currently but it becomes a whole other ballgame when something needs to be proven in court. The suggestion to make them legally mandated is where I think we run into problems.