I did also find this document from the OECD:
For example, in the case of loss or theft of a crypto-asset in Australia, the owner may claim a capital loss, provided they are able to present the evidence of their ownership.
So I am an Australian. I have Bitcoin in a wallet that I can prove belongs to me. For example, I purchased the coins on a centralized exchange where I performed KYC. I withdrew them from there to my wallet and that should be enough to prove they are mine. To avoid paying taxes, I "lose" my coins. I send them out over TOR to another Bitcoin wallet. From their, they get mixed, coin-joined, converted to Monero, gambled with, etc. Omg, I am so unlucky, someone stole my coins, but thankfully, I can claim capital losses.
I wonder what the Australian authorities would say to a claim like that.