The Chinese authorities insisted that Apple run its iCloud services through a Chinese business partner to stop the countries data being snuffled up by British and US spooks armed with a court order.
Apple was keen to help the Chinese out, after all, it is desperate to prop up its failing iPhone business behind the bamboo curtain. In fact, some considered them rather too keen and did a deal with local partner Guizhou-Cloud Big Data (GCBD) from February 28. GCBD is run by the Guizhou provincial government which will be able to monitor users whenever it likes.
According to Techcrunch, it turned that things are rather worse and that Apple is giving the Chinese iCloud accounts that were opened in the US, are paid for using US dollars and are connected to US-based App Store accounts in the data that will be handled.
Apple said that its terms and conditions site explains that it is migrating iCloud accounts based on their location, so if Apple thinks you look Chinese you will have all your data going to China: "The operation of iCloud services associated with Apple IDs that have China in their country or region setting will be subject to this transition. You will be notified of this transition via email and notifications on your devices. You don't need to take any further action and can keep using iCloud in China. After February 28, 2018, you will need to agree to the terms and conditions of iCloud operated by GCBD to keep using iCloud in China."
TechCrunch found instances of iCloud accounts registered overseas. One user did try to opt-out. That involved switching iCloud accounts back to China, then signing out of all devices. They then switch their phone and iCloud settings to the US and then, upon signing back into iCloud, the account will seemingly not be part of the migration.