My question is about an ISP forwarding foreign traffic.
So neither the source nor the destination is a customer of the ISP.
But the ISP owns a data cable which is part of the way from the source to the destination.
Will the ISP get money?
Such a question would be likely be off-topic for Network Engineering:
Network Engineering Stack Exchange is for asking questions about professionally managed networks in a business environment.
Now this is a professionally managed network (hopefully), but it does not meet
the following requirements
- under your direct control (if the network is not under your control you will not likely be able to provide the information required to answer your question);
- hardware that has a paid support option from the manufacturer (enterprise/provider class products, some small business class devices);
In defense of the other answer, I did find a well-received 'philosophical' question on their site: Network Neutrality, how does it actually work, technically speaking? so perhaps it might work.
I would think that it's more oriented towards understanding the business model of a certain company, and Economics would be a better candidate. But do check their Help Center before asking.
The best place to ask this type of question is the network engineering Stack Exchange site, at https://networkengineering.stackexchange.com/