Final answer:
The lawyer's position is likely unenforceable, as the senior commercial secretary is entitled to overtime pay regardless of her job responsibilities.
Step-by-step explanation:
The most likely position of the provincial labour board in this situation would be that the lawyer's position is unenforceable.
While the senior commercial secretary's contract provided for salaried remuneration and she oversaw the work of the junior secretary, this does not eliminate her entitlement to overtime pay.
According to labour laws, employees who work overtime are generally entitled to receive overtime pay, regardless of their job title or responsibilities.
Therefore, the denial of overtime pay in this case would likely be considered unfair and against labour regulations.