Surely this is an invasion of privacy and the befefits will be outweighed by poor staff morale it has caused. It won't stop someone stealing money... do you know how much cash you can hide in a shoe or your sock etc.? And what would be the company's stance if you left with less money than you arrived with (maybe you bought a laptop from a colleague), would you then have to explain your personal finances to the company?
Huge invasion of privacy for not much gain to the company.
Sorry, this has really annoyed me!