Is not that hard to concieve. Lets say you were diagnosed with a brain tumor which made you susceptible to outbreaks of violence. The doctor petitions the judge to prevent you from owning firearms and the judge revokes your right. With registration the legal system knows you have guns and how many. With no registration they have no knowledge of whether you have guns that need taking away. Prior to the mental illnes you had no plans to do evil.so you cant use the argument that bad guys wont follow the law anyway.
Or lets say you commit a violent felony. And can no longer have guns. With registration the state can enwure you follow the law but checking that you turned them back in or sold them.
Being "susceptible to outbreaks of violence" does not equal a history of violent behavior.
Rather than remove firearms from the patient's home and ban him from exercising his rights, why not just confine him? If he's that violent, then the absence of a gun will not make him less violent. He could grab a knife, a tire iron, a lead pipe or a baseball bat and murder someone in one of his "violent oubreaks."
What I'm getting at it, if the man is dangerous, petitioning to remove the man's guns would be ineffective. To look at it from the other angle, if he's not dangerous enough to be locked away for fear of hurting himself or others, then he's not violent enough to take away his right of self defense.
Maybe instead of a judge getting involved, the doctor might recommend having a relative take custody of the firearms. One thing people don't seem to understand or care about is, once the system labels you, it can screw you up in all kinds of ways down the road. Look at the crap going on with HPD and Kaiser/Straub. Seeking counseling for diabetes can get you flagged to deny you a gun.
So, instead of looking for the justice system to get involved in every single situation, how about we exercise common sense and treat people with the respect they deserve. We are so terrified of lawyers now, nobody wants to do what's right, only what's legal.