The idea is intresting, though there might be a better way to accomplish the wanted result.
There could be another type of creature all together that live in a symbiotic relationship with the rats. They use the debris the rats leave to create shelter. The debris can, when left and accumulated, cause a problem for the rats, possibly a breeding ground for a disease particular harmful for the rats. This other creature lives out of sight from the sentient species most of the time. But when rats are being repeadily killed they come out and attack viciously those who are attacking their source of shelter material.
This seems a more likely \"real\" solution to the camper problem.
