Earlier quoted context omitted.
It can be turned off in version 1511 for Enterprise and Education editions, under Group Policy: https://technet.microsoft.com/en-us/library/mt577208(v=vs.85... See screenshot and guide at http://www.ghacks.net/2015/07/30/windows-10-and-privacy/ Alternatively, disable this service if concerned: http://www.ghacks.net/2015/11/19/microsoft-rena-and-telemetr...
All can be turned off in Windows 10 Enterprise LTSB (Long Term Servicing Branch) - it's very expensive and not sold to consumer nor small business at all. But think about your doctor, your lawyer, etc. many smaller business, cheaper Windows 10 editon (non LTSB) they will unintentionally leak your confidential personal data. You say such PCs shouldn't be online at all? But they are and many of them run on Windows. Sca…
And almost certainly very illegal in a lot of places. Not only do you have whatever routine data protection rules apply, but in cases like medical data or legally privileged information there are higher standards required in many jurisdictions as well.