Exam Advice: How to Explain the Unforeseeable Plaintiff?

Beau Baez (Charlotte) writes:

Here is my recurring problem around final exam time:  how to explain to students when they need to discuss the unforeseeable plaintiff.  In most cases, the plaintiff is foreseeable, so on the exam I really don’t want students to waste time identifying and discussing a non-issue.  A seasoned lawyer will “know it when they see it,” but just as that was not satisfactory in the old obscenity cases it’s not a great response in this context either.  I am wondering how other torts professors explain this context within the essay exam context. 

You can either respond in the comments or directly to Beau at:  hbaez@charlottelaw.edu.