Rivet - I expect there is a permission in their AOC to operate IMC below MSA over water.
It's in uncontrolled airspace, so yes, you have to have some means of making an approach.
So let's say they have such a permission, which I don't doubt, what happens when they come over land in the water?
I know what you are saying, but the method of achieving that safely seems dubious or uncertain.
In Canada, operators who work in uncontrolled airspace have to construct "company routes' and have a company route manual, or a part in their ops manual. A route has to incorporate terrain clearance standards that are published, and it has to be approved before the regulator. If I remember, I think a company can do that on its own.
A company can't design its own approach, or it can but it has to be approved by an approved approach design firm. Didn't used to be that way but it is now. And then the approach has to be published in the Restricted Canada Air Pilot. Long time, not overnight.
The alternative is a cloud breaking procedure, which I'm thinking is a descent to MSA.
Sort of what went on here, but perhaps lacking regulatory approval and a requirement to comply with some standard.