This isn't just the "way I see it". This is the way it is. It's already codified. It's the law.
If they have a credible complaint, they notify the respondent either by arrest, if they have probable cause, or summons to appear in court whenever, if they don't. If he doesn't show, they issue an order for his arrest. (By credible complaint, I'm not talking about a neighbor that is mad because the neighbor's dog pooped in his yard, so he tells the police the man has been pointing his gun at him and pretending to shoot him)
Once he is in court, it is up to the plaintiff, or the court, to prove him either a danger to society or incompetent. Whereupon they will issue an order to seize any firearms he may possess. If necessary, they can keep him in custody and get a search warrrant issued to find any weapons.
All legal.
But this isn't quick enough or sure enough for the gun grabbers. So they craft a law to go around all the legal barriers in place to protect a citizen's rights.