Specially trained and reliable witnesses would certainly be a help. But, of course, they’re humans and thus fallible and corruptible. (Heinlein, a creature of his times, was a pretty big believer in institutions and professionalism. The past decade has largely served as a refutation of both. And even in his day, the institutions and professions were less trustworthy than we thought; it was just harder to find out when they were lying, sort of a meta-case of what I’m writing about here.)
Technology might help some, as it will probably soon be able to tell if people are lying via brain scans with high reliability. (I doubt it will be able to tell if they’re just wrong, though). And that technology offers its own set of – very troubling — problems that go way beyond this essay.