Anti-Theft Supermarket Trolley Invention - An Excercise For The Mind?

A group of engineering student at the Singapore Temasek Polytechnic is said to have invented a theft-proofed supermarket trolley as the answer to the frequently loss of trolleys from supermarket.

As reported in the local press:

"TRY to push this trolley out of the supermarket and what you will find is, the brakes on the wheels activate and the trolley collapses, dropping your groceries."

While this invention could prevent theft of trolleys, I personally question the economics of its implementation.

Supermarket trolleys are not that expensive to manufactured and basically they are non-intelligent devices and the materials use are mostly mild steel. To put in anti-theft mechanism like this would drastically drive up the cost of the trolleys. This extra costs is unlikely to justify the small number of trolleys that are being removed from the supermarkets.

Moreover, it seems like the anti-theft trolley is activated by moving over a hump, this means that humps have to build around the supermarket to trigger the trolley? What about legitimate use of the trolley when the shopper wants to push the trolley to a taxi stand?

This anti-theft trolley might seems impractical, but not all is wasted, the motion and shock mechanism that causes the trolley to fall apart could well be use in other situations