Getting into lifts in Adelaide and other parts of Australia is not the most pleasant of experiences. Generally people pretend others don't exist. Don't ask me why, but I think it might be something to do with our English heritage. Unlike other cultures where people will greet others as they enter, we just don't do that here. When we took our family to Mexico we were completely blown away by people's friendliness upon entering a lift. We must have seemed rude as we didn't respond at first, we couldn't get over that people had actually acknowledged us. Nothing worse that looking like a stunned mullet after someone has just said good morning.
If your brave and feel like fun, knowing that you'll never likely to see these people again, give it a go, just don't be surprised if no-one responds.
In Adelaide (and all of Australia), it is always polite to say hello (or g'day) and goodbye (or see you later). You may or may not shake hands but a lot of Australians have a "don't touch" policy to strangers. Always say please and thank you. This will get you a lot of mileage with Australians.