Isn't it better when machines do the dirty work for us homo sapiens:
Smart fabrics make for enhanced living
To make a bag that prevents people forgetting things, Nanda and Cable have
equipped a module with a radio antenna and receiver. The unit is programmed
to listen for signals from radio frequency identification (RFID) tags on
objects like cellphones, keys and wallets.
A sensor module in the bag¹s handle detects when the bag has been picked up,
indicating that the owner might be leaving.