"Then you'd have to wonder if that particular area had something special that needed protecting from foreign vessels getting too close in." It was the US that secretely tapped into their military communications cables for years in the same area. We specially modified a submarine to perform the 'tapping' operation. One of the US spies that we finally caught told them about our tap. So, a little paranoia is understandable.
I've read a lot about that story -- you're right about the location of the cable in question. The cable the U.S. was tapping lay underneath the Sea of Okhotsk, and was used for military communications between the mainland and the USSR's military facilities on the Kamchatka Peninsula. This has always been a very sensitive area for the Russians, due to its remote location and proximity to Alaska.
If you do a search on "Operation Ivy Bells" you should find some interesting articles about the whole operation, and how it eventually came to an end.