I have to agree with @wwf here. The biggest problem isn't people abusing the rewards pool but users not voting. There were studies done years ago where someone walking with a dollar drops it. What they found is that 98% of the time people did the right thing and brought that dollar back to its owner.

We don't need to focus our attention on the few who "abuse" the rewards pool. We need to focus on the majority who don't. Focus on what you want, not on what you don't want, lest you make what you don't want a reality.