It would be trivial for cell phones and PDA (Personal Digital Assistant)s to allow you to transfer money from person to person, or person to vendor locally or over the Internet with high security. Mugging would be pointless. You would just go to the police, explain you gave somebody money under duress, then they would know precisely who he is and his bank account and get you your money back even if they could not find him. Cash would disappear for everything but illegal transactions.
~ Roedy (born: 1948-02-04 age: 64)