> That's what jury instructions are for. The judge can instruct the jury to ignore pretty much any facts and consider any subset of what really happened that they want. So they'd just instruct "did they access the system? Were they authorized? If the answer to the first question is yes, and to the second is no, the verdict is guilty, ignore all the rest".
The only real protection is the fact that you can vote whatever way you want and not even a judge can compel you to state your reasoning.