Show me any Red Flag Law that does not operate under Due Process. All the ones I have looked at have a judge in the process.
A judge is also needed for a search warrant. Red flag in some states is the same as arresting the accused for what they suspect will be found before the search is made.
So you can't find a single Red Flag that does not involve a judge and due process? Such as evidence or testimony?
The guy in Maryland was Red Flagged and then killed by the police before his guns were taken. Where was his Due Process?