Chris Jermyn and Bill Shorten
Liberal candidate for McEwen Chris Jermyn confronts Bill Shorten in Sunbury.

For better or for worse, one of the elements that may come to characterise the 2016 federal election is the "gotcha" moment during political interviews.

It’s not that gotcha journalism is a new phenomenon -- Richard Carlton famously confounded and infuriated Bob Hawke by asking if he had "blood on his hands" after replacing Bill Hayden as Labor opposition leader in 1983.

Ten years later, Liberal opposition leader John Hewson was similarly confronted with a less obvious but apparently equally tricky question about the application of his proposed GST to a birthday cake.