#Witch hunters

What you have isn't a balancing issue, it's a law enforcement issue. Your solution should be an in world taboo or law enforcement system. The power spike is detected by the enforcement agents and they respond. Anyone using such a method is automatically flagged as "dark" by the rules of "good" simply as a result of the amount of power they're drawing.

Excessively heavy handed law enforcement for the few laws they're able to enforce always has a place in a world. Mary-Sue automatically gets flagged for her base power level because of this monitoring and the story begins.

Witch hunters

What you have isn't a balancing issue, it's a law enforcement issue. Your solution should be an in world taboo or law enforcement system. The power spike is detected by the enforcement agents and they respond. Anyone using such a method is automatically flagged as "dark" by the rules of "good" simply as a result of the amount of power they're drawing.

Excessively heavy handed law enforcement for the few laws they're able to enforce always has a place in a world. Mary-Sue automatically gets flagged for her base power level because of this monitoring and the story begins.