I rarely pick up our household phone line if I don't recognize the caller. On the other hand, I also give it out to clients as an emergency way to contact me, so when the caller id read "New Jersey cell phone," I figured I'd better respond even though I couldn't recall a single New Jersey resident I'm working with at the moment.
So I said the usual "Hello," which triggered the strangest recording in telephone history. "Oh, we're very sorry for dialing the wrong number. If you would like to be taken off our list, call (800) blah-blah-blah-blah."
A recording knows it has the wrong number by the fact I said hello? Or that I answered in the first place? Wow. The Do Not Call list is a useless piece of legislation these days, isn't it?