In the case of the laptop tracking service, a knowledgeable thief could rewrite the BIOS to turn off the dial-home feature (because once enabled or disabled, you can't change its status), intercept the dial-home connection between the laptop and the Internet, or never connect the laptop to the Internet. But like Lojack, and nearly every home alarm system, the idea is to convince the thief to bypass your hardened target in favor of easier prey. Of course, to create that incentive in the laptop scenario, the owner would have to post a large sticker on the laptop saying, "Don't Steal This Laptop, It Notifies the Owner Of Its Physical Location" or something like that.
Other laptop-security offerings realize that the majority of the value is not in the stolen hardware, but in the data it contains. Many vendors offer remote data delete services; Absolute calls its service Data Delete, and Microsoft has a similar feature in Exchange Server 2003 Service Pack 2. Many tape backup and storage companies have these types of services as well, and there must be more than 100 similar products for PDAs, cell phones, and other mobile computers.
Essentially, remote data delete services place a piece of agent software on the device to protect either the entire storage medium or selected pieces of data. The deletion agent software is designed so that it dials home as well, and if given the appropriate signal, starts deleting (or encrypting) data.
Many of the products include a feature that allows the data owner to enable automatic data deletion if the mobile device hasn't contacted the remote management site in x number of days. However, that's one to be cautious with. You might get sick for three weeks or stuck on vacation during a hurricane and could end up with your data deleted. Fortunately, many remote delete agent programs have a local password override.
With nearly half of all data theft incidents now involving stolen mobile computer devices, expect services like these to become the norm in the next few years. I encourage readers to investigate similar products and vendor offerings. It's great peace of mind.