I understand what you are saying, but I don't think it is quite accurate. Someone who is pardoned has to be pardoned for a reason just like they have to be convicted for a reason. Therefore, in order to pardon someone is has to be specifically stated why and there is no way in hell they can "admit" their wrongdoing even though we already know exactly what they did.  The things we don't know yet are all the details of how. And the hows themselves can, and most likely, are crimes as well. And finally, I don't know if someone can pardon themselves. Which is why Ford pardoned Nixon even before a trial.