I think it has to. The only way it could not is if you had a piece of physical evidence, and you were going to extract the technical evidence from it there in the courtroom in front of the jury. But even then, you have to worry about the chain of custody of the physical evidence, and about the tool you're going to use to extract the technical evidence in the courtroom...
Perhaps it does but I'm not convinced without evidence it happens and I can't find any that shows it happens the majority of the time let alone all the time :/
Well, I think what happens in an actual court case is, you check out the chain of custody if you suspect that anything is actually fishy, or if you can make the prosecution's case look weak. If there's nothing there that you can use in your defense, then it never comes up in court.