They did release the weights and there are many providers https://openrouter.ai/deepseek/deepseek-v4-flash-0731#provid...
Deepseek's official API has a pretty bad privacy policy so I would assume businesses avoid them in any event
Yes, I assume US customers are more likely hobbyists, but in any case this off-peak designation can only mean that most of their business is domestic.
Interestingly it seems that Chinese customers are even more privacy-concerned than US ones, which is why the majority of Ziphu's (GLM) business is support services to Chinese companies running their open-weight models on-prem!