My answer to the question is no, but I am a pilot, and my expectation is an invalid input is recorded but is a no op. It is fly by wire so why not just no op the request? The idea such input suggest sabotage, is more paranoid than cautious. And shutting down the engines is hardly fail safe. It's just less fail danger than engaging the thrust reversers.

Quite a few turboprops have beta range that is supported for use in-flight. The purpose is to increase the rate of decent, similar to slipping the plane. So it's not always an invalid input; it's make/model/phase of flight specific.