Depending upon the age of the alumnus who offered the advice it is highly likely the interview format will have changed since they were interviewed. Alas, gone are the days when you could spend the interview talking about cricket and still be offered a place. As above, you can't predict who will be interviewing you. The interviews aim to find out how you think, how you respond to questions in an unfamiliar context and to demonstrate your problem solving abilities.
Far better to talk about what interests you in the PS.