Linnet Taylor correctly points out that US case law does not have applicability outside the US. However, the third-party doctrine set out in the Smith v Maryland case differentiated between transaction-generated data on a telecom network and the content of what was communicated. Now there’s likely to be a different governing precedent, for those under US law:
The Supreme Court agreed on Monday to decide whether the government needs a warrant to obtain information from cellphone companies showing their customers’ locations.
The Supreme Court has limited the government’s ability to use GPS devices to track suspects’ movements, and it has required a warrant to search cellphones.
The new case, Carpenter v. United States, No. 16-402, concerns historical data held by cellphone companies that shows users’ movements over time and could, for instance, place them at the scene of a crime.