Sure, but computer chips are probably the most complicated things that our civilization can currently make.
Asking somebody to prove that a computer won't do X is a fool's errand, outside of some shrinking safety-critical industries.
That said, you could always make your own smart speaker with a hardware button or shell script instead of a wakeword:
https://developer.amazon.com/en-US/docs/alexa/alexa-smart-sc...