I’ve visited Australia as a traveler, apparently I’ve heard that “burner” phones over there are not really anonymous since they literally demand for ID (WTF? That defeats the purpose of it being classed a burner phone) otherwise they aren’t allowed to sell it to you, what’s meant to be a ‘disposable’ phone turns out on buying a regular one when you consider the fact they ask for driver’s license prior to finalizing the transaction.
Don’t even talk about SIM cards for BP, since that too is subjected to KYC in Australia as I’ve learned. They want to harvest data such as driver’s license & residential address (for citizens), or passport info / flight confirmation (return ticket) if you’re a traveler. Without those things: vendors can’t legally sell you a burner phone, so: DON’T BUY A BURNER PHONE IN AUSTRALIA. Their method of acquisition defeats anonymity.
It all used to be very easy in Australia, you bought the phone at a supermarket and gave bogus info when registering the SIM. Then the “War on Terror™” began and the government started taking things a bit more seriously started mandating the paper registration forms needed to be completed or the retailers could get in trouble. But your average supermarket worker wasn’t going to take the time to do that and it was way too widespread for the government to actually crack down on it.
Took a few years but the Telcos started actually paying attention to the fact that the majority of prepaid phones weren’t getting completed paperwork at point of sale so they just moved to make all sim card activations require online or over the phone ID checks.
Every bit of training I ever did made it clear it was all about catching terrorists, drug dealers and paedophiles, which of course means “We want all that juicy data without citizens asking any annoying questions.”