Okay, let's apply this argument to nonwage work in our own societies. If people slack off when they are not "fully compensated" for their labor, no family would function. As I (and many other list members) can testify, we do all kinds of noncompensated labor in our family life without wage compensation. Yes, there are all kinds of direct and indirect social sanctions to encourage people do to family work, but we're definitely doing it outside the wage system, and for the most part, the work gets done.
I've said it before, but the point is worth repeating: in terms of GDP, about 1/2 of the work that we do in the U. S. to sustain our society is done outside the wage system. This demonstrates we do not need direct economic incentives to get important social labor done; we just need socialization that a particular form of unpaid labor is important and meaningful.
Miles