Because:

A) You are not regularly expected at any particular place at any particular time.

B) You are regularly expected somewhere - but no one at that place would be particularly concerned if you did not show up.

C) You live alone.

D) You live with roommates - but they would not be particularly surprised or concerned if you did not come home.

E) You would like to think that someone might get an email if you didn’t login to this website.

F) You would like the email to look like this: