This goal has the following fine print specified by pjh:
In order to work around internal Beeminder limitations, this goal is fed using callbacks from http://bmndr.com/pandf/gmailzero
This has some limitations, for example the zeno polling only works if the source graph is in the red, not if this graph is red. And the callbacks aren't 100% reliable yet. q.v. http://bmndr.com/pjh/callback
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