The decision 'to take or not to take' the picture is yours. This decision should be, first and foremost, informed. Whatever the situation is ask yourself a few questions first. Am I breaking the law? Is the other person breaking the law? Is it worth it?

In the nutshell. Street photography is perfectly legal in Australia. No one has a right not to be photographed in a public space ("A person, in our society, does not have a right not to be photographed." John Dowd in a 2001 case (R v Sotheren)).

Photographing a private property from public space is perfectly legal. Don't let the mall cops tell you differently. Shooting a building on a street = ok. Photographing IN the building, supermarket etc. MAY be restricted, you may be asked to leave and stop photographing. I say fine, stop and eave. They DO NOT have the right to confiscate the camera or ask you to delete anything. This is illegal. Always be polite but firm, write down the names, use your phone to record the event if things escalate.

Use common sense when photographing people on private property. Do not be sneaky or hide, remember, you aren't doing anything wrong.

Case is different if you are trying to do something wrong, people have right to privacy in their homes: pestering, stocking, trespass, nuisance, criminal intent, indecent photographs of children are obviously bad. You will and should be punished if you're involved in any of the above.

You do need consent of all people present and recognizable in your photographs if you want to use them for commercial purposes. Is an art exhibition a commercial purpose? This is tricky. I'd say no, you may sell a few prints but you did not take the photographs with the intent of making money.

Stock photos, commercial campaigns, ads etc. are clearly money making operations and there's nothing wrong with that as long as you have permission. Enter model release. It's rather simple: taking photos with intent to sell? Get the signed model release. 

Police officers are not walking encyclopedias - they do not know the law to the letter. Be polite but firm in the event of confrontation. Educate them if you can. Ask for badge number, names and the reason for their interest in you. Record if things escalate but stay safe.

Print this out and carry in your wallet or camera bag.

Obviously, check the law in your state, reach out to art organizations, AIPP, a lawyer etc to be sure. Check these blogs and articles for further reading and more details.

• Arts Law Centre of Australia
• The Sydney Morning Herald
• analysis of legal issues which apply to street photography in NSW Australia PDF
• there is always Google