There's a huge difference between holes in roads or sidewalks which you can see and avoid, and your boat falling through the interior wall of your house to a non-existent space in limbo between the realms of inside and outside. A better example would be that if some sidewalk slabs were actually interdimensional portals to some other dimension you could never return from, disguised exactly like normal cement slabs, and you were telling people it's their fault if they fall in.
The house is surrounded by black. This has always been before and is also now used to mean that the space is empty, and outside of the playable area. You can't walk into it, place items into it (normally), nor interact with it in any way. Why should it be common sense that if you take a boat inside it's going to be sucked out into this not-space? Just because you're familiar with a bug (and it is a bug. The developers did not design this blackness as a boat sucking monster) does not mean that everyone who ever plays the game should become immediately knowledgeable of it.