I think the best way is to follow the exact words in Section 60D(2) of the EA:
"60D(2) Any employee who absents himself from work on the working day immediately preceding or immediately succeeding a public holiday or two or more consecutive public holidays or any day or days substituted therefor under this section without the prior consent of his employer shall not be entitled to any holiday pay for such holiday or consecutive holidays unless he has a reasonable excuse for such absence. "
However, law is one thing and it may not solve the problem. In the case mentioned by you, if it is true, the employee looks like he is taking advantage of a weak HR. This should not be allowed to happen. Otherwise, things can get out of control when more are going to follow his way.