True, but they do know what the boats are doing and it isn't fishing. If they were fishing, they would be flying a flag of a specific country. Operating a boat without a flag is the same as flying a plane without filing a flight plan. You can object to the rules of engagement but they are in line with hundreds of years of maritime law.
I've never seen a fishing boat fly a flag, and I've been sailing in many countries for >20 years. Generally, fishermen don't care for such things.
So, since I am British and have a UK registered boat and know a bit about this. The law that applies (The Merchant Shipping Act 1995 section 5) requires that we should fly the flag when entering or leaving a foreign port or upon a signal by one of Her Majestys ships [1]. Flying a flag routinely in international waters is very much not required, and very few vessels fly a flag out there, because there is not much there to look at it and it just flaps itself to bits.
That sounds very much like a cultural thing. Here in the Sound (the strait between Denmark and Sweden), the norm is definitively to fly a flag with so many different nationalities sailing here. In Sweden it is also required (through not punishable) to carry a flag if you are around the port, when in visible range of the coast guard, when in foreign waters, and when in visible range of other ships in international waters. The only exceptions to those requirements is participation during sports events.
With the trouble brewing with the Russian shadow fleet in the Baltics, flying a flag seem quite important unless you want the coast guard to stop you (they have also increased their presence significant the last 5-10 years and do a lot of random checks).
Are shady Russian private military organizations or whatever just completely unable to get their hands on a Norwegian or Finnish or Estonian flag or something?
Who needs stealth when a cheap piece of fabric provides cover.
They seem to be able to more easily acquire flags of convenience from further away, and optionally some kind of nominal insurance from different providers likely to pass muster at a first glance (I have zero maritime expertise and just wanted to add some supplementary context to the parent of your post).
> Operating a boat without a flag is the same as flying a plane without filing a flight plan
You seem to really equate this with the idea of planes flying without filing a flight plan. Are you OK with the US military shooting down any plane that doesn't file a flight plan, without even trying to communicate with the vessel or intervene in any other way previously, even if that vessel doesn't appear to be heading towards any specific US territory or vessel? Is that also allowable under international law?
No. You're not supposed to be bombing any boat you find in international waters that doesn't have a flag on it for whatever reason you can come up with.
