It's not that Microsoft is "not cracking down," but rather that everyone is complying with Microsoft. Microsoft offers
Windows 11 Arm VHDX for free as a preview. Apple silicon is unsupported, but that's only a blocker to having some confidence from Microsoft that it will work. It's not a compliance issue with Microsoft's
licensing terms for the software.
Preview builds are probably not suitable for enterprise use in most cases because Microsoft is explicitly indicating that the software is experimental. They aren't making any support guarantees, and reliability and security efforts could be low compared to commercial general releases. Microsoft could even make low level changes to Windows ARM that breaks on apple silicon, as part of the normal course of development.