USS Cole was in Harbour and anchored when it was attacked by a fast moving fiber glass boat. Your example does not fit.
But for the record, the fishing boat did not receive any warning, and even if they had, they did not have to react to warning, since they had right of way as per Marine law. The Captain of the Ship is on record saying that no warnings were given.
If the marines made a mistake, they will now pay for that mistake.
It may be unfortunate, so now let them deal with the result of that unfortunate incident as per the Law.
There is every reason to seek Justice for the murder of Indian Citizens. The Stress of Italian marine is not our concern. They are not our citizens.
I am seriously saying that I do not care what Italy thinks and I am pretty certain no body in India cares. You are in no position to either 'allow' or 'not allow' us. At most you can 'protest' peacefully.
The solution is to finish the trial and punish the marines if they are found guilty. That is the most peaceful solution.