Every calendar I have seen in the United States starts on Sunday.

From which statement we can deduce that (a) Mrs Doe is in the United
States but simply hasn't seen all that many different calendars, or (b)
Mrs Doe has seen calendars not starting the week with Sunday but didn't
see them in the United States, or (c) Mrs Doe isn't in the United States
in the first place and has seen zero calendars there.