PS re: "I want my personal information secure from casual passers-by who after having a quick peck on the keyboard would more than likely give up; I'm not looki

PS re: "I want my personal information secure from casual passers-by who after having a quick peck on the keyboard would more than likely give up; I'm not looking for PRISM dodging security here :-)" How about an RFID tag fixed to your wheelchair, and a transceiver for it mounted on your computer desk?