When you click through the Windows 10 "agreement," you agree to let Microsoft subject your games and hardware to authenticity tests and to shut down anything it doesn't like the looks of.
As intended, this allows the company to impose extrajudicial punishments on you for offenses that it gets to make up on the fly. They're banning "unauthorized" hardware — if it comes in a box that says "Compatible with Intel motherboards," and then spoofs the board to trick it into operating with it, is it "unauthorized," or just a third-party replacement part that does what every third-party printer cartridge does already?
But then there's the unintentional consequences: Microsoft could get it wrong. You could unknowingly get an unauthorized part in your system, provided by a manufacturer (who may also be unaware of the fact), and have your machine brick itself just as you're about to do something critical: give a big presentation, administer anesthesia, or provide air-traffic control support to a stricken jetliner.
And then there's what happens when (not if) Microsoft gets hacked — by crooks or spies or police forces — and pushes out the killswitch command to anyone they don't like.
Section 7b – or "Updates to the Services or Software, and Changes to These Terms" – of Microsoft's Services EULA stipulates that it "may automatically check your version of the software and download software update or configuration changes, including those that prevent you from accessing the Services, playing counterfeit games, or using unauthorised hardware peripheral devices."
The list of services covered by the agreement doesn't explicitly include Windows 10. However, it does include your Microsoft account, which is an extensive part of the Windows 10 experience, as well as core features like Cortana – and that implies Redmond can disable any games you've pirated or devices you've "unlawfully" hacked. Enable Cortana (which pretty-much everyone using Windows 10 is going to do) and you're subject to the Services agreement.
Microsoft can disable your pirated games and illegal hardware [Vaughn Highfield/Alphr]