Unless I'm mistaken, the relevant copyright laws aren't limited to enforcement when money exchanged hands.

No, but it does matter how much money the alleged infringer has.

Property law is mostly concerned with protecting the rich from the poor, so when a rich person violates the property of a poor person, the courts can't allow the inversion of purpose and will create something called a "legal fiction," which is basically the kind of bending-over-backwards that my children do to try to claim that they didn't break the rules, actually, and if you look at it in a certain way they were actually following the rules, actually.