Good Accessory for a mobile phone

This is for somebody who often forgets his/her luggage while on travel. Take two or three RFID (Radio Frequency Identification) enabled cards and put them in ur luggage bags and the cellphones have to be enhanced to keep track of the luggage when you are around. Incase u have moved out a distance with out ur luggage the cellphone should give an alert. This feature can be extended to monitor ur valuable items as well like wallets etc. Cool thing to have on our mobiles is'nt it?