With the calendar set to Month view:

1) An all day event on March 10 displays normally -- only on March 10.

2) An all day event on March 17 displays across two days -- March 16 and March 17.

3) For what it's worth -- an all day event on March 14 displays normally but when opened for editing, the end date is displayed as March 13 and on saving and closing triggers the error message "The end date that you entered occurs before the start date." On all other days I've tested, the event end date is always correct, regardless of whether the all day event displays across one or two days.