Transport Workers Union $($TWU$)$ and Metrorail $($Pty$)$ Ltd entered into a collective

agreement which entails the following: $10\%$ salary increase, a $5\%$ house and vehicle

allowance. Further, the parties agreed that this dispensation was effective for three

years and applied across the board. Two months later, a group of the highest paid

employees in Metrorail lodged a complaint that, the increase should not apply across

the board because, for them the benefits were all taken away by the South African

Revenue Services $($SARS$).$ The $10\%$ salary increase, the group explained further, put

them in a bit higher tax bracket, and increased their liability towards SARS which

effectively takes away all the benefits. They argued that although the employer gave

them an increase, SARS took it away from them. They, therefore, demanded a $15\%$

increase to remedy the unfair situation.

ANSWER THE FOLLOWING QUESTIONS WITH RELEVANT AUTHORITY:

$($i$)$ Assume that Moshishi and Mvala are not members of TWU. Can the abovementioned collective agreement apply to them as well?