Astro, while on the surface when someone "works to rule" the performance or output might be different, proving that in the Commission will be quite a task, when a Commissioner will just as easily turn around and ask the employer - "what is expected of the employee(s) under their agreement/contract".
An employer can't just come in and say "well this person usually works to this level which is above the terms of their contract etc etc" and think that would satisfy an unprotected IA claim.
Even if an employer has certain implied expectations of it's employees the contract is the contract.