I know what the term “scare quotes” means, but I don’t know its origin. Does anyone know?

Addendum: Michael Dummett uses the expression “sneer quotes” to refer to the use of quotation marks (either single or double) to distance oneself from another person’s terminology (Michael Dummett, Grammar and Style for Examination Candidates and Others [London: Duckworth, 1993], 85). This makes sense, since the person using the sneer quotes is sneering at the other.  But “scare quotes”? What’s that all about? Who’s being scared, and why?