It used to happen all the time. When my ship was engaged in NATO exercises in the N Atlantic in 1968, the Soviets used to send out patrols all the time, not just to gather intelligence, but to actively disrupt our operations. One of their destroyers actually maneuvered itself into a right-of-way position with us and forced us to do an emergency breakaway during a refueling operation.

They tried it again a few days later and our skipper had rehearsed an appropriate response. Our ship and the oiler we were receiving from actually changed course and cut across their wake, while we were still rigged together and transferring bunker fuel. In those days, the Soviet Navy didn't even have a fully developed UNREP capability and they were flabbergasted. They were good sailors, but that kind of seamanship was just beyond them.

We were also buzzed frequently by long range air patrols that photographed our gear and monitored our freqs. I remember one Bear (actually, a prop 4-engine strategic bomber modified for maritime recon work) came so close I could see a cameraman in the Perspex blister between wing and tail taking pictures of us.

There was a recon Bear lost (with no survivors) while buzzing an aircraft carrier later that year, and the rumor going around the fleet was that it had been shot down.