So are you saying that if a child does some cleaning at the KH under the supervision of their parents this is legally child slave labour under AU law?
It's certainly the case that under 16s did get involved in KH projects in the 80s in the UK but I know it was not allowed at AH construction level even then. They enforced an under 16 rule pretty quickly in the QB days in the 80s and over the past years the processes and procedures for getting onto a site have been gradually made more and more rigorous to the point that there is no way kids can be involved even in a casual way.
I know this similar practice is followed in the States, Europe and certainly on any large build worldwide so I'd be surprised if similar processes were not in force in Australia.
On top of this under 16s and those not "approved" have not been able to be involved with most aspects of assembly related volunteer work for a long, long time now, the only exception being cleaning that I can think of where kids helping their parents is still allowed (as far as I know).
I understand the legal ramifications of what you are saying but do you think that current practices within the WTS can be classed as child slave labour?