Yes, just like it prevents the prosecution from bringing in a cop that will testify against you to the court. Yes, just like it prevents the prosecution from b

Yes, just like it prevents the prosecution from bringing in a cop that will testify against you to the court. Yes, just like it prevents the prosecution from bringing in a hair expert that will testify to the court that your hair was on the crime scene. Yes, just like it prevents the prosecution from bringing in a blood splatter expert to testify to the court only you could make this specific splatter. As you can see, truth or efficacy isn't a prerequisite of being admitted by the court.