This just happened:
Him: "Hi, I'm calling from (worthy cause), I'd like to..."
Me: "Sorry to interrupt, but we have a policy that we don't donate to charities who solicit by telephone."
Him: "That's fine. Of course I wouldn't ask you to give money over the phone. If it's okay with you, I'll send you an envelope by mail."
Me: "No thanks. Good luck with your other calls."
Him: "What? No?"
Me, patiently: "You're asking me this over the phone. That's solicitation."
He got very angry with me for some reason. Oh well.