Editorial: The town would not need to spend as much as it does on removing trash if all town residents sorted their household garbage.
Conclusion
The current system in which people voluntarily sort their garbage is preferred to one in which the city tells the residents they must sort their garbage.
Evidence
If people were told they must, many would comply but many would refuse. The city would barely save any money but it would engender a lot more resentment.
Evaluation
We're being asked about an idea that was not in the author's argument. The first claim was the reason why the city would consider doing the mandatory plan. Our author argues that the current voluntary plan is better, because the supposed benefit of the other system (cost savings) would be minimal, compared to its negative repercussion (fostering resentment).
Goal
This claim was the supposed benefit of the plan that the author is rejecting.