1. Reporting Pay: I believe you would have to pay employees 3 hours of reporting pay under Sec. 11.1 of the Labour Stds Reg.
Reporting Pay
11.1 An employer shall pay an employee who reports for work at the call of the employer wages for not less than three hours of work at the employee’s regular rate of wages, whether or not the employee is called on to perform any work after so reporting for work.
2. Pay for Full Day: Under the CLC and Regs, if the employee reports to work and fails the medical screening, you’re only on the hook for the first 3 hours. Of course, there’s more to life than the CLC and your company may have an obligation to pay a full day under an employment contract or collective agreement, HR policy or past practice. If there is no such contractual, HR policy or past practice requirement, then, no, you don’t have to pay for the full day. Same analysis applies to employees who are scheduled but don’t report to work. Neither the CLC nor Regs address this issue, so it comes down to your contracts, HR policies and/or past practices.
Caveat: Be careful because failure to pay for a day could expose you to liability for constructive dismissal or even discrimination to the extent you don’t follow the policy consistently and treat members of a protected class, e.g., race, sex, less favourably than others.
Great Qs and I hope this helps.