It's expensive, easy to bypass, and has little enforcement teeth.

Expensive because you need to pay an inspector (ideally multiple to avoid corruption) to visit these farms.

Easy to bypass because the kids aren't working the fields all the time and there's plenty of warning an inspector is coming.

And the enforcement mechanism is you don't get the label... But like there's plenty of buyers for slave chocolate so that mostly means a minor hit on income.

NGO inspectors are better than nothing, but we should be clear eyed in how much they can solve. The only way to significantly reduce slave labor is harsh penalties on companies that trade in slave goods. That was pretty much the only thing that collapsed the ivory market.

You could buy a large plot of land in Ghana or Nigeria. Start a large cacao plantation. Hire locals to do the labour intensive work for you. And then fly in management from Western European countries to oversee the operation and to make sure that no children set foot on the plantation.