I've had someone use it against my mum in a job interview(I mean that I'm mentally ill and will be a burden), and have had old 'friends' spread things I told them in confidence, which came back to me in the form of being called a retarded ****** through email.
However, as hurtful as this is, I think I'd rather be on the receiving end than to actually be one of these deluded and narrow minded people.
They are mindless robots who cannot be trusted.

Sorry if this seems harsh, but it's proved true to me.