The Electronic Frontier Foundation breaks down the implications of this massive power expansion: "this change would grant authority to practically any judge to issue a search warrant to remotely access, seize, or copy data relevant to a crime when a computer was using privacy-protective tools to safeguard one's location." An effort to protect privacy could actually make one more susceptible to government intrusion. This is less about the means by which agents may search and more about the geographic and jurisdictional reach of a particular court. Google, joining about 30 other agencies commenting on the rule change, called it a "monumental" Fourth Amendment violation.
Here is the actual language:
A magistrate judge with authority in any district where activities related to a crime may have occurred has authority to issue a warrant to use remote access to search electronic storage media and to seize or copy electronically stored information located within or outside that district if: (A) the district where the media or information is located has been concealed through technological means; or (B) in an investigation of a violation of 18 U.S.C. § 1030(a)(5), the media are protected computers that have been damaged without authorization and are located in five or more districts.The second change, (B), is of less concern; the first, however, has drawn criticism for its vagary and the possible unintended consequences. Possible impediments to judicial review include ex parte application procedures and the invocation of good faith and qualified immunity to escape actual judicial resolution of substantive challenges, according to Congressional Research Service, in Digital Searches and Seizures: Overview of Proposed Amendments to Rule 41 of the Rules of Criminal Procedure.
The other controversy swirling is how the rule was changed--by a rather obscure judicial rule-making committee that has power to correct mistakes or change procedure. But this change is substantive, and many believe it should have been subjected to full Congressional scrutiny.