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.
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"
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)
You can be saying you support it on the condition that it’s implemented poorly enough that it should be circumventable. That just doesn’t make sense.