Oops, hand slipped. My significant other has caller ID. Any call she gets which is listed as "unavailable" we don't answer. If it's someone who knows her/us,they leave a message and we can pick up. Otherwise if we have to pick up the extension without checking caller ID, she will answer the phone "Yah, hey!" and they'll usually hang up. I also have answered saying I'm Susan Urban's Butler and they also hang up, if they are not familiar with us.