One of the points raised in the letter:

"One point that has been revealed is that data may only be accessed if they originate from non-US persons and are collected from sources within the US. The WP29 would however like to know when US authorities consider personal data to be inside the US, especially given the continuously increasing use of the internet for processing personal data, where much information currently is stored in the cloud, without knowing the exact location of the datasets, and following the global scale of backbone networks and their inherent capability to convey a wide range of communication services."