Computing history is chock full of examples where something "seems to work" but is actually invalid (and a mach-O treated that way would be invalid [EDIT: or just "not accepted" by some parts of the system, see below], whether it runs or not), and then Raymond Chen has to write a blog post about it decades later. Here's just one out of many as a random example: https://devblogs.microsoft.com/oldnewthing/20041026-00/?p=37...
Back to this particular case, the binary will fail strict code signing validation on macOS. It may still run because the kernel does not access the binary past the coverage of the code signature (and all the bits there are still intact), similar to how multiarch binaries work, but you will at least severely be hampered to distribute your binary, since Gatekeeper won't be happy either.
Back to this particular case, the binary will fail strict code signing validation on macOS. It may still run because the kernel does not access the binary past the coverage of the code signature (and all the bits there are still intact), similar to how multiarch binaries work, but you will at least severely be hampered to distribute your binary, since Gatekeeper won't be happy either.