That still seems for a single station. Meaning that you leave it there and hope someone will get the message. On the case we include real-world coordinates and other relevant data that is clear text like npub. This way couriers can pick the ones that go on the same physical route as them and leave these messages a bit closer to the intended geographical region. The message content can be encrypted but that isn't mandatory. Some couriers don't feel comfortable transporting messages that are hidden, due to liability. Those systems are probably great. Just feels that they never really used them on the ground and are huge theoretical exercises. For our case we have a community where even this week electricity and internet were away for days. So this kind of messaging on the ground is necessary.