When a man armed with a loaded assault pistol strapped to his leg, dressed in camouflage, and singing to himself began walking in front of a Grand Rapids, Mich., church one snowy Sunday morning in March 2014, an alarmed churchgoer called 911. When police arrived, they took the man's gun, and briefly handcuffed him while they questioned him. The man, Johann Deffert, an "open carry" gun advocate, then sued police saying they had violated his constitutional rights, reports the Detroit Free Press .

A federal judge disagreed.

In a decision released last week, U.S. District Judge Janet Neff tossed Deffert's lawsuit, saying the police officer "was justified in following up on the 911 call and using swift action to determine whether plaintiff's behavior gave rise to a need to protect or preserve life ... in the neighborhood."

Neff's decision comes as police agencies around Michigan are grappling with increasingly contentious clashes with gun advocates who are showing up at places like churches, schools and government complexes armed with assault rifles and handguns, part of their campaign to educate residents on gun laws, and desensitize the public to the sight of guns.

Michigan's controversial "open carry" laws allow people with concealed carry permits to take guns into so-called pistol-free zones, such as schools, as long as the weapon is visible. There is no state law regulating open carrying of weapons in other areas as long as the weapon is in plain view, according to Michigan State Police.

Now courts are weighing in, and state lawmakers are reviewing the laws.