Your organization purchases a single Volume License Key (VLK) for Windows 10 Pro. Someone in accounting thinks it is a "magic key" and installs it on 200 laptops. For months, nothing happens—because VLKs often have a grace period or use KMS (Key Management Service). But if the KMS server goes offline, or if the machines lose contact with the corporate network, every single laptop will phone home to Microsoft simultaneously. The "shower" begins.

Journal of Digital Forensics, Security and Law , Vol. 12, No. 3 (2017) Discusses how product keys are stored in the Windows Registry (e.g., DigitalProductId ) and methods to recover them.