Actually, analogies abound.
Though nasty and crude, I like my "hostage for ransom" analogy the best, as it really gets the point across.
You (infringer) are being held hostage with a huge ransom demanded. You have three guns (patents) pointed at your head. You discover that two of the guns aren't loaded. Do you argue for a lower ransom? Vulnerability unchanged....
JMHO,
SGE