How do shopkeepers know the difference between stolen and legit trade commodities?

Right now, it's just a flag that we have internally. In the future, again, it will be that it's just a continued flag that they have. As far as the interaction with the shopkeepers, that to me is something that we have yet to work out, like how we want them to kind of question you and say, is this good? Or how did you come about this kind of thing? But right now, it'll be dealing with kiosks.