Why does that matter? That’s a question about the implementation of the law.

You can’t go “I support the law if it’s implemented poorly so I can circumvent it, but I don’t support it if it’s implemented effectively and I can’t circumvent it”

The question of if it should be the law should assume that it’s implemented effectively, if people will only support an ineffective easily circumventable implementation then they don’t actually support the law and should vote against it.

It mostly matters because like all good laws it will likely be used to erode privacy in an effort to enforce it.

In context with the assistance and access act 2018 this is just another step towards the encryption with government backdoors future ASIO have been calling for in order to "protect us"

But what is "effective" in this case? My kids use huge Whatsapp groups as a form of social media, will Whatsapp be banned? Using a VPN to access TikTok from outside Australia is not beyond the skills of a determined kid, will VPNs be banned?

Those details matter to say whether or not this is a good idea, why not wait until you have the answer to those questions before enacting the law? (I think there are no good answers too this, and it's probably better to say this is a job for the parent, not for the government)