To me, there's a considerable difference between any hostile action against a NATO member and a non-NATO member. With regard to Georgia in 2008 or Ukraine in 2014, they were non-NATO members. If Russia were to do something similar with the vessels of a NATO member, the consequence would be absolutely out of proportion with what's happening now.
To me, it's a completely different cost-benefit calculation on the part of Russia, and I would not necessarily extrapolate to what it means in terms of potential threat for NATO members or NATO as a whole.