Actually a billing provider is not requirred to check your licenses to see your content is licensed, but they are requirred to revoke your billing option if actions is not followed from a DMCA notice. They are however if they are based in USA, requirred to check that there is valid 2257 links on sites they do billing for, again a valid 2257 link does not actually mean that you hold the license for the content. If y3ou steal content, why not steal 2257 docs too?
Unlicensed content does not actually mean stolen content, it could be a human mistake, just as a DMCA could also be send out by a mistake as well.
An example could be someone working with a portfolio of companies for different business areas, and by mistake take content licensed to company A and use for combany B, ofcourse this is not licensed, but this could be a honest mistake by the business manager that run both company A and company B.
Would you feel good if I spend example $10K on content in your shop buying content for a company, and by a mistake put up lets say 2 sets on a site owned by another company I run, the result could be you DMCA ccbill that pull billing, after that you discover I bought a shitload of content from you, and you killed one of my online business rather getting me a "warning" to clean up my shit. And in case the above scenario happend, do you think you would have a repeat customer from me?
I'm not saying that this is something I speculate in, but I do hold a lot of licenses for various content, and also content licensed to different companies, so it COULD in theory happend, I do belive I have multiple of your sets too
