I have seen this done for classes, but the problem sometimes becomes students look at it as a exercise in adding content but ignore Wikipedia guidelines.  They end up adding essay like material, add information that makes existing tags worse in order to add material related to the course, etc.

Speculating, I would think a potential better criteria might be adding references to uncited materials related to the topic as there is a lot of unsourced material.  They would be adding pure bytes by adding sources.  It would also assist in making them more familiar with other sources that you may think valuable for them to be aware of.
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