Shrubbery

A plausible path is precedent and normalization, not zsh specifically.

If a widely used copyleft component (like a shell) starts being accepted as “OK to lock down” in consumer or embedded devices, manufacturers and courts get comfortable with the idea that user-modifiable software is optional rather than a right tied to distribution. Over time, that erodes enforcement of anti-tivoization principles and weakens the practical force of copyleft licenses across the stack.

Once that norm shifts, vendors can apply the same logic to kernels, drivers, bootloaders, and userland as a whole—at which point locked-down embedded devices stop being the exception and become the default, even when the software is nominally open source.

You put on your black hat at work when your boss tells you to do so on objects under your teams ownership.

But that’s white hat, not black hat.