I wonder if release clauses were signed,
I don't understand this argument. This isn't about private parties and covenants not to sue.
This is about whether certain government agencies are responsible for certain patches of ocean and are obligated under some law or treaty or other to mount a rescue when a rescue is required.
If that is so, and it frankly seems quite plausible to me, then there is no "release" to be had here. Governments in 2023 presumably don't allow people to say "don't rescue me" if they have the obligation to, in fact, rescue them. Which then raises the question of whether they can intervene in situations they regard as high risk and also whether they actually do so.
I have visited lesser, land-based wilderness areas and once you leave the trailhead, you really are largely on your own as little as 500 yards down the trail. You may or may not run into others and they may or may not be able to help you. There are rangers around if not commonplace and I imagine that you might be able to ask for, and receive, some kind of rescue if you needed it and were able to get the word out to the authorities lurking just outside and somewhat within the wilderness. There is no cell phone service and basically nobody carries satellite phones to the places I have gone. I don't recall anybody being helivac'ed out, but I am sure it could happen, depending.
But I do not remember having to provide or sign up for any kind of specific safety plan. We got briefed on how to handle brown bears (the most likely problem) and that was it.
Whether these places, in these much more dangerous waters, are more strict, I don't know. I could easily imagine it being so, given the order of magnitude greater risk of death.
But, I do know that whatever is done ahead of time, to go to any wilderness of any kind puts you in a place where rescue is
chancy and cannot be counted on in the first place. Just pure personal survival means that something had better be planned and nobody should
expect a timely rescue. You basically need to assume you will rescue yourself or at least that's the percentage play. That means, among other things, your boat needs to be robust enough to at least limp into some port, somewhere pretty much no matter what happens.