It's a Class A misdemeanor in Wisconsin. Still a crime though
Age 16-18 open-carrying a long gun is EXPLICITLY legal in Wisconsin as long as the person has a FOID card. (He did-WI accepts an IL card.)
Let's see your evidence of this ... show evidence he had a valid FOID card and show evidence Wisconsin makes exceptions for minors with an Illinois FOID card...
Gun laws in Wisconsin - Wikipedia
Firearms and minors
Leaving a firearm within reach of a child under 14 is generally a misdemeanor if that child points it at anyone, harms anyone, or shows it to anyone in a public place. Defenses include having the gun locked in a safe or container, having it holstered on their person, having a trigger lock on the gun, removal of a key operating part, illegal entry by anyone to obtain the firearm, or a reasonable belief a juvenile could not access the firearm.
Firearms retailers are required to provide every buyer with a written warning stating, "If you leave a loaded firearm within the reach or easy access of a child, you may be fined or imprisoned or both if the child improperly discharges, possesses or exhibits the firearm."
Upon the retail commercial sale or retail commercial transfer of any firearm, the seller or transferor shall provide to the buyer or transferee the following written warning in block letters not less than one-fourth inch in height: "IF YOU LEAVE A LOADED FIREARM WITHIN THE REACH OR EASY ACCESS OF A CHILD YOU MAY BE FINED OR IMPRISONED OR BOTH IF THE CHILD IMPROPERLY DISCHARGES, POSSESSES OR EXHIBITS THE FIREARM."
Defenses to prosecution under this statute:
- Target practice under the supervision of an adult
- Members of armed forces or police under 18 in the line of duty
- Hunting (either with an adult or having passed hunter's safety)
For hunting purposes, the following exceptions to the age limit apply, as specified in statute 29.304[35] for firearms with barrels 12" or longer.
- under 10 may not hunt with a firearm or bow under any circumstances
- under 10 can only possess firearm/bow in Hunter Safety class, or while cased/unloaded and under adult supervision while going to/from Hunter Safety class, or while under adult supervision while at a target range.
- anyone age 10 or over may hunt when accompanied by an adult (within arms reach, both must be licensed, only one firearm/bow between the adult and mentor (no hunter safety course requirement for the mentored hunter).
- 12-13 may hunt when accompanied by an adult and the child has successfully completed a Hunter Safety class.
- 12-13 may possess firearm when accompanied by an adult, or while transporting cased/unloaded firearm to/from Hunter Safety class, or in Hunter Safety class
- 14-16 is the same as 12-13, except Hunter Safety graduates can hunt and possess firearms (rifles/shotguns) without adult supervision.
School students shall be suspended until their expulsion hearing if they possess a firearm in school or during a school event (except if the student is participating in a Hunter Safety class). State law requires a minimum one-year expulsion for this offense. Statute 120.13(1)(bm)[36] and 120.13(1)(c)2m. In addition, the student's driver's license may be suspended for two years under Statute 938.34(14q).[37] This suspension also applies to students who make bomb threats or having CCW violations in taxpayer-owned buildings. § The age range has changed for Minors. Link included to Wisconsin statute. [38]