Unintended consequences: donated mosquito net edition

Ethan Zuckerman points to a Zambian blogger claiming donated mosquito nets are used by fishermen for destructive drag-netting in rivers and streams. A bit of googling turns up similar stories in Namibia and Rwanda. I wonder if these are marginal cases or if the practice is truly widespread, and if people who pay for mosquito nets are less likely to use them in this way.