NATO and US ships are for decades exercising in the Black Sea. And these are not "paramilitary" boats, sometimes cruisers and destroyers. I have not heard that Russia was overconcerned until anybody was going to enter its territorial waters.
Even this well-known incident
https://en.wikipedia.org/wiki/1988_B...mping_incident was not considered as a "casus belli" at all. It was understood that it just was check of the quality of iron that seamen balls were made of :-)