Anyone who says they can do these things is mentally deranged. So too the people who believe that others can do those things and deserve to be killed.
So let PNG have a national championship for sorcerers. Bring all sorcerers wearing masks if they wish and put them on TV to explain what they can do. Then let them do it for a prize of K100,000. No tricks.
Let the TV news report each night to the nation that no sorcerer turned him/herself into a bird or bat. None has flown out the window. All are hungry and demanding their dinner.
Let the news report at the end of the competition that no sorcerer has won the K100,000 prizes as no magic has been done. Let that news go out to all the potential killers of old men and women in the highlands.
Sorcery is not real but limited to tricks people play on the minds of others. No human being can influence the environment in magic ways. They can never call up snakes or lightning strikes. They can never influence landslides or earthquakes.
Only poison or fear are real. No so-called sorcerer will go home from the national sorcery championships K100,000 richer. They can not do those things even for a big prize.