[Clubber]

I would say that is part of the scope. The scope being a well tested, functional and relatively bug free software that does x, y and z.

[Terr_]

Unfortunately most business people don't make things like "doesn't corrupt the database when an exception is thrown" into a feature bullet.

So while you can argue it's part of the scope, it's not part of the scope that anybody else seems to think about.