I found this fascinating quote today:
"I think what would work better would be to say that there was a shortage and people tend to buy more of something that's in demand. (Laughter.) We saw that -- there was one season where, really, people lined up all night to get a flu shot." Simonsen says, much to the amusement of the other attendees at the symposium.teodoroleonIII, Teodoro Leon 3 News Column, Nov 2009
You should read the whole article.