1 Iki Piki: How are we supposed to sell our cargo if nobody’s here to buy it?
2 Serron: Maybe we can just find the cash supplies and do the exchange ourselves.
3 Iki Piki: If they just left a bunch of cash lying around, why wouldn’t we just take it all and leave nothing?
4 Serron: That’s what I just said!

There could be an honesty box, but it'd be tricky to find with the Vantablack everywhere.

And Serron is probably unfamiliar with the concept anyway.

Honesty boxes are common in rural and semi-rural Australia, mostly at homes that grow fruit and vegetables and have modest excesses that they leave in a box at the front gate, with a smaller box for people to leave cash if they want to buy some. On a trip to Tasmania I bought large bags of apples this way.