If this statement is not correct, then how can impersonation work under the context of the sa and dbo? Is the meaning here implying that impersonation is not used when the context is dbo or sa? Or is it implying that only the objects that the sa has referenced can be impersonated and not the sa status? (Ditto I suspect with the dbo). If the latter is the case, then this particular case, where one has "absolute" power in the database [dbo] or on the server [sa], is considered an exception?