You can thank Brett Walton (Segway dealer on the Gold Coast) and Transport Minister Scott Emerson. In 2013 they got together to have the legislation passed. For some time, police were using Segways at Southbank. I suspect this aspect had a lot to do with letting the rest of us use them publicly. The original Segway weighs about 55-60 kgs, so a bit awkward to stuff into your plane.