Should charities threaten potential donors?

Earlier this year, I blogged about my dislike for charities who try to guilt donors by mailing out unsolicited gifts. While I find this to be an offensive practice, my friend Tom recently received a mailing from a charity called Smile Train that may have topped this. (In case you're wondering about the picture below, Smile Train "is dedicated to helping the millions of children in the world who suffer from cleft lip and palate").