The legal system maintains strict rationality about this point, and judges will sometimes use this cleverly. In order to give a clear analogy, let's say that you get into an Internet Argument about how if the Ontological Argument for God worked, then we should be able to summon Perfect Doughnuts In Our Hands into existence just by imagining them. (I don't know, it's just an example.) Someone comes by and says, "aha, you're wrong! You were saying that doughnuts are the perfect baked foodstuff, when in fact they are inferior to muffins!"
It is a fully rational response to say "(a) I wasn't saying that, and don't require that, and (b) muffins suck, doughnuts for the win." If you can argue those two points, then either one would rebut the criticism. So too is the form "I didn't do that, and even if someone did do that, that's not illegal."
In this case, her lawyer is providing lots of different arguments why the original threat-to-sue makes no sense. First off, she didn't do it; second off, it wasn't registered at copyrighted at the time; third off, etc. ... and lastly, even if it was supposedly copyrighted, the Constitution did not give Congress the power to issue such copyrights.
The many defenses are very useful to judges, who can then be clever. If this case got appealed on the last ground to the Supreme Court, they might essentially say, "you've given us a thorny question of Constitutional law, but we're not going to answer it, because it's our determination that she didn't commit the offense and was not responsible for it simply due to leaving her wireless unencrypted." This has happened before, where the courts accept an appeal and then postpone a sweeping judgment to a case where it actually matters because they don't want to set a precedent one way or the other.