Thanks for this important and challenging question. I don’t know the laws in Australia, as I’m in the States, but you could possibly get professional liability coverage, also called an Errors and Omissions policy, which doesn't cover physical injury (which you wouldn't need with distance sessions), but does cover advice. This is known as a professional liability policy and the kind of insurance that all kinds of service providers, including life coaches, often use. I don't know what it might be called in Australia or if it exists there, but if you can get this kind of policy, it should cover you.

In most cases, the laws and courts of where you're practicing are in effect. In other words, if someone from the US wanted to sue you, they'd have to go through the Australian courts and follow that process, which, depending upon the claim, may be more effort than it's worth. This does not mean it’s ok to act in ways that might be harmful to clients, take advantage of them, or be negligent! Whether you might be sued or not, that kind of behavior is never ok.

But because there are numerous principles of jurisdiction, especially on the international level, there are ways to get around someone having to sue you in Australian court, so I encourage including in your Terms of Service that all suits are required to be filed in the courts of your Australian jurisdiction. 

So yes, signed and even unsigned waivers can be legally binding. Even a properly worded disclaimer or Terms of Service that follows the laws of your jurisdiction that doesn't include a required signature can hold up in court, provided that they are made clear to clients. I am no lawyer, and this does not constitute legal advice, so please consult with a legal professional. Standing Stones Healing Co. cannot be held liable for any errors or omissions, and by reading this article, you agree to proceed at your own risk. Except nothing is without risk and so if someone really wanted to sue you, there are ways to get around that. But keep using a disclaimer!