The status of news media and journalists are in many legal systems defined as special.
In Norway the Section 125 of the Criminal Procedure give journalists and media companies a special role, and the right in many circumstances to refuse to give up information or answer questions related to sources.
So keeping the servers within the full control of the news organization seems as a wise choice also here. It also gives the option to stall in order to put in place the necessary legal counter measures from legal departement / outside council.
In 2015 we had a significant case of the Police Security Service (PST) seizing the video recordings of a documentary film maker in order to try to use it as evidence in a case against islamists recruiting people to go to Syria for terrorism.
The case went all the way to the Supreme Court of Norway where the PST where finally refused to keep and use the seized material due to the risk of revealing sources.
In the case the Article 10 of the European Convention was central, and might be relevant for many European countries. The Norwegian Supreme court stated that the European Court of Human Rights “sets up broad protection for unpublished material that may reveal unidentified sources.”
A good summary of the legal facts in the case and the references to European Convention and similar cases at the European Court of Human Rights can be found here:
https://globalfreedomofexpression.columbia.edu/cases/rolfsen-association-norwegian-editors-v-norwegian-prosecution-authority/