Would there be less spam if Mechanical Turk cracked down on jobs like this?

Is this even against their policies? It strikes me as a hard policy to write. Compare it to "write and distribute a whitepaper about XYZ". That certainly sounds like a legitimate task, but it is only different from this example in scale.

At least if they decide to to forbid this practice, they can pay their own turksters to find and flag the forbidden activities.