The PPCA licence is only required if your going to be playing at a public event such as the Sydney Music Festival in the domain at a local festival in the street . Private Events such as your mates 21st at home or a wedding you don't need a PPCA also it is not enforced. I did inquire with them. I am a mobile DJ only doing private events as long as the music has been purchased legally. If you intend in doing people's events as a business you need public liability insurance.