Seriously, I think all cell phones (and TV remotes!) should come with some sort of homing beacon or an inbuilt GPS locator device!
Telemarketers keep calling on a daily basis but since we got Call Display a few months ago, I usually know now when not to pick up. That way no one's time is being wasted and I don't have to insist in a stern voice that I have no intentions to explain my reasons for rejecting their sales pitch! "A No is a No is a No! Comprende?"
