I agree, but that they were built and designed with evil intent, would take a close examination to extricate that type of control systems.

In some cases it might be one where once the control systems are removed that what remains is no longer functional.

As an analogy, there are some video games that would do the copy protection requiring a connection to the server for verification. If you remove that server, then the whole game stops working because the verification system requires it to start. (Yes, it can be cracked to spoof, but the rest would lose that function).