They don’t sell that brand in my country so I can’t speak for the wrapper but I checked the Wikipedia page for the company and their website. The wiki page doesn’t really help with the claim but provides some helpful context for how the company was founded and about Tony himself who you could say did indeed go out and check in his capacity as a broadcaster, though prior to forming this company.

I think it’s probably more accurate to say that Tony’s puts high standards and systems in place in addition to external certification programs to make it more likely that when they’re assured that production in their supply chain doesn’t involve slavery, it’s more likely to be true. I guess we haven’t set a definition for what going out and checking vs taking someone’s word for it means here but to the extent that I wondered how exactly they were able to physically go and inspect without endangering themselves the answer seems mostly to be that they don’t actually send people from the company to go and check as far as I can see. I think it’s worth pointing out as well that they’re probably not best viewed as a good manufacturer in contrast to a Fairtrade certified manufacturer because they seem to think those certifications are good and credible and are themselves Fairtrade certified, it’s just that according to them that’s really only a baseline minimum to try to avoid slavery creeping in to the supply chain. The other steps they take seem to be more around fair practices and traceability to make slavery less likely to occurr and a lot of this depends on their careful selection of partners and the formation of co-ops.

The closest claim I could find that resembles my interpretation of the idea that they go out and check rather than just taking the word of a supplier or external certification body is something they have an article about on their page called Child Labour Monitoring and Remediation System. CLMRS seems to be a set of practices that co-ops that Tony’s has partnered with are encouraged to adopt and relies upon volunteers from the community (unclear which community, is that the co-op or the physical area where most members are from?) to go out and inspect so that’s pretty close to what you say. Their description of this system is entirely focussed on “families” found to be employing child labour and child labour specifically as opposed to anything else. None of this is a critique of this approach I should say right now, but in terms of the claim of how they go about actively checking for themselves rather than taking the word of others, this approach seems a little more complicated than that and not entirely aligned with that description. It’s volunteers from a community not Tony’s representatives or employees, and they’re specifically focussing on a kind of slavery where such a form of inspection could reasonably be done with any safety where it’s household farmers likely using their own children for labour. Their approach to that specific situation is great I should add, and doesn’t just cut people loose likely making the problem worse and tries to work with them to eliminate the practice.

Great though they sound and certainly an option I’d consider if I could, I think from my initial research that the fact that the closest thing to your claim is CLMRS and that this is done by the co-op themselves, with verification done by unnoficial volunteers, not Tony’s themselves, and that adopting CLMRS seems not to actually be mandatory to become a Tony’s partner does I think put the idea that Tony’s checks rather than just accepting claims in to a different and more nuanced light.

I will express once more it sounds like to my non-expert ears that they are doing this right and I don’t criticise their approach, I’m just clarifying because based on what you said I was imagining people from Tony’s making random inspections of cocoa plantations that may have many types of slavery going on (not just child) and which may be run by more sophisticated criminal networks that might violently defend their interests rather than just family run farms.