Laptop Security prevents Laptop theft?

Recently one of my friend returned home in the evening to find out that her New Toshiba Laptop which she uses for her personal usage got stolen. The headache is she has stored all her SSN, Bank details in it and ended up calling the credit agency  and banks to monitor the usage of her SSN and bank accounts.
And today I got a mail from my company security department to install the Computrace software in the business laptop they had given me as part of the compliance. I was just curious to knew about the available softwares for laptop security and how they work.
It seems these software installs a software tracking code in the laptop’s hard drive and they electronically trace it when its stolen. It’s just a lojack for the laptop. Here on the available companies that offers these solutions. Cyberangel work when the laptop connects to the Internet and secretly reports the location of the laptop. Computrace Personal offers a similar service through a three year contract and agrees to pay up to $1000 if your notebook computer is not recovered in thirty days. Ztrace is a company offering an interesting twist to laptop tracking. They offer a facility to remotely delete or encrypt sensitive files on your laptop after it is stolen. I have no idea on How reliable they are.