Nedra at Spare Change has written an excellent post on fear appeals that had me reaching for my Xanax. She has some great suggestions on how to make a fear-based campaign more potent. Be sure to check it out.
I haven't experimented a lot with fear appeals as a cause marketer. But I have no doubt they would be useful to Boston Medical Center. One angle is to exploit middle-class fears about losing health coverage so Bostonians will realize how fortunate they are to have a hospital that provides "Exceptional care. Without exception."
The risk in using fear appeals too frequently or too severely is that your audience will tune them out, and your organization along with them. Fear appeals, and other emotional messages, need to be balanced with appeals to trust and logic (Aristotle called them pathos, ethos and logos). Sure you can pluck your donor's heartstrings, but don't forget that character and sensible arguments can move them as well.
The American Red Cross ran plenty of emotional ads last fall to goose donations to Hurricane Katrina relief. But when donors saw news reports that the Red Cross was disorganized and ineffectual in the Gulf region, money went to rival organizations, especially The Salvation Army, that had trusted reputations and better track records. (Don't be too proud, General. Charity Blogger reported recently on a credibility crisis brewing for the Army in the UK. Will nonprofits ever learn?).
My advice for using fear appeals is the same for going to a scary movie: don't go alone. You should always take your friends, ethos and logos.