I've had pets all my renting life and I've never actually told my prospective landlords/agents about them.
I find that there is a LOT of prejudice against people who have pets when applying for properties and that it's easier just not to mention it.
Sure it's deceitful, but given the state of the rental market in Melbourne, you could be looking for months and months for someone that is pet friendly.
That said, my pets have never caused damage and I make sure I am a top notch tennant in all other ways.
I treat my rentals with the uttmost respect and have always had really positive comments from my landlords as to how well I maintain them.
When I lived in the UK they often made people pay a 'pet bond' so that if they caused damage they were covered. it's a shame that more people in Australia don't do this as it is a really good idea.