In war, false flags are flown -- not too often -- but often enough and with devastating results if not countered that unless the potential combatant is positively identified -- by radio calls, for example -- you just take them out and ask questions later. Hot war does not provide the decorum and comfort of asking questions first. That politeness is deadly -- suicidal.
If I were an "intelligence" gathering agency, I might possibly have a reason to NOT inform the combantants as to why I was sailing in international waters. Hmmm?