If I was on a jury I think I'd have trouble avoiding applying my own logic if it was obvious to me the defendant didn't have a good lawyer..
During the trial in question, I tried very hard not
to hold the defendant's painfully ill-prepared public defender against him . . . but it wasn't easy.
Even still, I didn't think we could consider arguments and defenses (like "mistaken identity") that hadn't been aired in court. Our job was to examine the arguments and testimony placed before us, not to try to do the public defender's job for him.
Getting back to goofs, I still remember the M*A*S*H episode where Radar was shown reading an AVENGERS comic book--despite the fact that THE AVENGERS debuted some ten years after the Korean War!