mrs Weston seems to think it a delicate subject -- re chap 24, when Emma asked Frank whether he knew that Jane's situation in life -- to be a governess

"You know Miss Fairfax's situation in life, I conclude; what she is destined to be."

"Yes -- "(rather hesitatingly) -- "I believe I do."

"You get upon delicate subjects, Emma," said Mrs. Weston smiling, "remember that I am here. Mr. Frank Churchill hardly knows what to say when you speak of Miss Fairfax's situation in life. I will move a little farther off."

"I certainly do forget to think of her," said Emma, "as having ever been any thing but my friend and my dearest friend."

Emma thinks of Mrs Weston as her dear motherly friend and part of the family rather than as a former governess. Perhaps others in Highbury, remembering that Mrs W was once a governess -- instead of regarding her as an expert on governessing and asking her about it -- felt that it was a bit awkward to discuss the subject with her, as it involved her former "situation in life" and class issues?