Note I am borrowing  from a real life example Graeber borrowed from
one of the anarchist societies  he lived in while anthropologising.
So  my  theorising   might clash with Graeber's   ghost,   and  the
currently   living  innately  anarchistic  but I came up with  this
example I thought demonstrated real life night sorcery: 

Imagine   three people in a fairly homogeneous  anarchic   village.
Person B is one of many similar fisherpeople,  and person  C is one
of many similar  fish-smokers.   Person A does some equations,  and
concludes  that if instead of the relatively  unstructured  way the
fishers   are  bringing  in their catches,  and  fish-smokers   are
getting, smoking, and disseminating  smoked fish, if B and C form a
committed team of fisher and fish-smoker, they will begin operating
more efficiently  than the rest of the village. This daily positive
flux  of value  relative  to the other  villagers  is split  evenly
between persons A, B, and C. 

What  I  have  found  by talking  to people  is  that  it's  pretty
intuitive  person  A can be seen as being doing  something  morally
wrong   in  this  scenario,  even though  person  A is  the  iconic
capitalist hero character.  Person A has had an idea to restructure
the village from being flat, to funneling value 

1)  Person  A's  proportional  value relative  to the  village   is
increasing passively 

2) Persons B and C are accruing proportional value from the village
through efficient labor 

My understanding  of a villager  having delved too deeply  into the
power of Night Sorcery  by destroying  other villagers'   lives and
cannibalising them is prototypically person A. 

In contrast, persons B and C without a person A could cooperate and
this  culling  of advantage  is also night witchcraft,  but not  an
insane  indulgence:  Perhaps  they could also marry,  in which case
deeper coordination is implied.