How would that work? Businesses are liable if they trade with an entity that isn't on the OFAC list but turns out to be a shell company of a restricted entity?

How would that work? Businesses are liable if they trade with an entity that isn't on the OFAC list but turns out to be a shell company of a restricted entity? Each company needs to not only do KYB and ensure compliance with OFAC lists, but also somehow figure out UBOs for every customer too? Sounds like a lot of work to me, probably not viable for any but the biggest companies, and even they would struggle.