Nancy shield

From Voice of the Proletariat

When blatantly unwarranted down-voting of posts is observed in a discussion thread, bN users will often vote those posts back up, and become very proactive in voting up subsequent posts in that thread to preempt the down-voting. This is said to be the application of a Nancy shield, since the Pillow Biting Nancy of a culprit will see a big jump in their Nancy Metric.