Loosing gadgets everywhere

The IHT has a funny piece about tgis new fact: people have more and more gadgets but they are losing them more and more by "misplacing them in airplanes and airports, hotel rooms, restaurants, cabs and rented cars."

A study conducted by Pointsec Mobile Technologies, a mobile-data protection software company in Chicago, found that the number of laptops abandoned in one London cab company's taxis rose 71 percent in the second half of last year from the same period in 2001, while the number of personal digital assistants left behind shot up 350 percent. (...) The plague of forgetfulness has given rise to several services that locate vanished goods. Trackitback, in Winnipeg, Manitoba, and at www.trackitback.com, uses coded identification labels and a reward system to encourage people to call a toll-free number when they find a lost item with the affixed label. A lifetime fee of $9.99 covers standard shipping costs.

How can designers create stuff with a "presence" reminder so that the object is not left aside on the sidewalk after you made a break and alsmot forget your powerbook?