Dangerous Weapon Problem

What arguments can you make for and against criminal liability in the following scenarios?

Statute (§ 568.250):

Whoever, not being legally authorized to do so, knowingly carries a dangerous weapon into or on the premises of a correctional facility of this state shall be guilty of a felony.

Definitions:
"Dangerous weapon" means any firearm, loaded or unloaded, or any weapon from which a shot, readily capable of producing death or serious physical injury, may be discharged, or a switchblade knife, dagger, billy, blackjack or metal knuckles.

"Correctional facility" means any prison, jail, secure mental facility as defined in G.L. § 234.560 or secure youth detention facility as defined in § 254.120.

By statute, law enforcement officials are authorized to carry dangerous weapons. Section 235.150 limits those permitted to carry firearms in correctional facilities to sheriffs, police officers and correctional officials (including wardens and prison guards). The defendants in the following scenarios do not fall into any of these categories.

Scenarios:

(1) Defendant #1 goes to what he knows is a correctional facility to visit his cousin. He is not carrying a weapon. Someone #1 does not know realizes he has a gun in his possession and needs to get rid of it. He bumps into #1 and slips the small gun into #1's coat pocket. #1 is found with the gun and arrested.

(2) Defendant #2 carries an unloaded gun into a correctional facility. He knows it is such a facility and that he has the unloaded gun. He defends on the grounds he didn’t know an unloaded gun constituted a dangerous weapon.

(3) Defendant #3 is carrying a rifle he intends to use while hunting at the Hillside hunting area. He enters through a gate marked "Hillside" - no trespassing," thinking he is entering the Hillside hunting area through an infrequently used gate. In fact, he enters the grounds of the Hillside Youth Detention facility. He is arrested on the grounds with the firearm.

(4) Defendant #4 is carrying a small firearm that he is licensed to carry. He goes to visit a friend’s child at the Hillside Youth Detention facility. He is discovered carrying the weapon and claims he did not realize that a youth detention center is a correctional facility.

(5) Defendant #5 is a state wildlife agent authorized to carry a weapon. He goes to visit a friend in jail while carrying his gun. He is arrested and claims he thought that, as a wildlife agent, he was authorized to carry such a weapon in a correctional facility. Unfortunately, state wildlife agents are not among those listed as authorized persons in § 235.150.