Another commenter here mentioned that Starlink user terminals include a GPS receiver, and report their coordinates back to Starlink. That'd create an alternate vector for locating maritime users – exfiltrate that position information from their servers.

I had a hard time finding confirmation of this online (lots of hits about Starlink potentially being used _as_ a GNSS), but one of the photos of this teardown of a terminal highlights the GPS receiver: https://arstechnica.com/information-technology/2020/12/teard...