To wrap this up.. I did manage to get in contact with the authors of the article.
Many of you were right, they were looking for seasonal/winter moorage. They have an oldish steel boat, apparently no insurance and no resources for the required survey in order to get that insurance. So despite the comments they made, this would be nothing out of the ordinary, and likely nothing 'new'. Certainly our marinas here require proof of at least liability insurance.
The article was posted last February and may well have been written many months prior to that, so the 'new' element was overstated or perhaps misunderstood by some of us.
It would also appear that the liability coverage is not a requirement for transient overnight moorage, so the concerns that came up here among some cruisers who frequent US waters is unfounded.. (though anyone up here with permanent moorage would be well covered in any case)
I think the 'hot button' was the reference to 'an enormous amount' of coverage without stating just what that meant..
Thanks to all who contributed here, Case closed, I suppose...