If you don't want a source used in civil courts you can just tell the courts they are't allowed to use it.
That's what is done for accident investigation. Accident investigators need to understand what actually happened, not just a bunch of useless backside covering as everyone tries to avoid getting sued. So, their evidence just isn't admissible in civil courts. An investigation by, say, the NTSB or analogous organisations in many developed countries produces a public report, but you can't take that report into a civil court because it says in the law and on the report that it can't be used that way.
It would probably take more effort to ensure this was effective in the revenge-hungry United States of America than in countries where the mainstream zeitgeist incorporates the understanding that hurting somebody else doesn't fix anything, but it could be done.
That's what is done for accident investigation. Accident investigators need to understand what actually happened, not just a bunch of useless backside covering as everyone tries to avoid getting sued. So, their evidence just isn't admissible in civil courts. An investigation by, say, the NTSB or analogous organisations in many developed countries produces a public report, but you can't take that report into a civil court because it says in the law and on the report that it can't be used that way.
It would probably take more effort to ensure this was effective in the revenge-hungry United States of America than in countries where the mainstream zeitgeist incorporates the understanding that hurting somebody else doesn't fix anything, but it could be done.