Microsoft to "periodically" check Vista installs for piracy

Microsoft claims that its technology built into Vista allows the company to periodically evaluate the OS to make sure it is legitimate, rather than just having one opportunity, when the product key is first entered at activation.

This raises the question what happens when the activation check fails for invalid reasons?

Most failed validations, approximately 80%, are caused by a misused or stolen volume license key. The remaining 20% of the failures have a variety of causes, including tampering, hacking, and working around product activation. Across the more than 300 million validations, only a small percentage of validation failures were found to be in error.

Of course Microsoft has its right to protect their intellectual properties, but even a small percentage of validation failures with legal copies will cause a lot of customers to be upset. Another challenge to overcome?