Magistrate judges issuing warrants is normal -- they do most of the day-to-day evidence work outside of trials.
a magistrate judge with authority in any district
8 where activities related to a crime may have
9 occurred has authority to issue a warrant to use
10 remote access to search electronic storage media
11 and to seize or copy electronically stored
12 information located within or outside that district
13 if:
14 (A) the district where the media or information
15 is located has been concealed through
16 technological means
(edit: added language from the PDF -- key is the "if")
(edit 2: Original headline was "FBI seeks automatic warrants against users of VPN and Tor (p. 338) [pdf]" since it's going to get changed)