I'm curious if anyone here has any first-hand insight on this, as I can only go on hearsay: the claim is that if you're known in the court to have trained in martial arts, you're apparently held to higher standard or something like that, and the duty to retreat can be imposed on you even in a stand-your-ground state. I don't know if it's true or not, but I've heard a lot of people say it.
What I do know is that there's no national or international database or clearinghouse that the head instructor enters your name into that the police can access when you sign up to train. So unless the person you defended yourself from knows you personally, then keeping your mouth shut about your martial arts training should get you through. Assuming there's a need to do that in the first place.