It's relatively trivial, you just need to write a kernel module. You'd just need/want to make it gpl so everything it does is fully audited and transparent. That's not a problem, is it? Right?
From a technical standpoint, you could argue that someone could create a fork of the kernel that spoofs the interface that the anticheat uses to make it ignore things. You can, of course, also do something similar in Windows, but security theatre never let practicality get in the way.