According to Chapter 48, what are some common traits of spiritual teachers who should not be considered true Sadgurus?

The text of Chapter 48 provides several examples of individuals who should not be mistaken for a Sadguru. It states that simply having knowledge of the six Shastras or the ability to please an audience with talks about Brahman does not qualify someone. Furthermore, the chapter describes teachers who give mantras to disciples but offer no certainty of when the spiritual fruit will be attained. A key critique mentioned in Chapter 48 is directed at those whose knowledge is purely theoretical and whose explanations, while sweet, are "verbally hollow" due to a "total lack of self-experience." The chapter explicitly states that one who has no direct experience themselves should never be called a Sadguru.