Not legal in Australia unfortunately (it's a bit more nuanced, but many types of secret warrants are already immune to warrant canaries -- so I'm sure a judge w

Not legal in Australia unfortunately (it's a bit more nuanced, but many types of secret warrants are already immune to warrant canaries -- so I'm sure a judge would see that these types of secret warrants probably have the same protections). However they do allow statistical information on how many requests they received in a 6-month window.