I did not do anything.
You guys should be safe with yourselves.
Anything illegally taken will not be admissible.
Be safe!
I am not quite sure that is how it works. The inadmissibility of illegally obtained evidence is largely for criminal trials because it stems from a 4th amendment violation. The 4th amendment does not protect against other non-government actors. Even in criminal trials there have been convictions based upon evidence gathered from non-government informants illegally. In civil trials, which is what anyone here would likely be involved in (I personally have already contacted my lawyer to form a class action suit), admissibility is generally easier. The only concern becomes whether or not the emails can be authenticated. The DKIM signatures should authenticate them unless it can be proved that the signatures are faked, for example someone breaks into their server and gets the private key and can then generate anything.
Generally speaking the plaintiff would not have to prove that someone did not break in (proving a negative is always difficult) but rather GAW would have to assert a defense stating the emails are not valid because someone broke in and provide evidence that someone in fact did break in, that the private key was probably compromised, etc. Then its up to the majority of jurors to decide which side they believe. It would be less likely that a judge would just disallow the evidence but rather leave it to the jury to decide if they believe it to be trustworthy in this situation (although anything really can happen in the courtroom).
Civil trials are preponderance of the evidence not beyond reasonable doubt and you only need 2/3 of the jurors so its often easier to win a civil case than a criminal case. When officers of a company commit crimes as part of their business practice, especially fraud or deceit, it becomes easier to pierce the corporate veil and go after personal assets and other holdings outside of what the company has left.
I am not a lawyer, I am just a poor law student trying to get a job to pay for school after 20+ years working in the computer industry. Hire me to develop your next bitcoin app so you can take over the world