> Or to be blunt: correctness should not be opt-in. It should be opt-out.

One can perfectly fine write correct programs using mutable variables. It's not a security feature, it's a design decision.

That being said, I agree with you that the author should decide if Zen-C should be either mutable or immutable by default, with special syntax for the other case. As it is now, it's confusing when reading code.