Currently when you add a lookup field for a date the new field will have the formatting options of local format and GMT time zone. This is confusing when the original field is set to be local timezone. It can appear that the wrong date is being shown.
A better default seems like it would copy the formatting options of the field being looked up, but that these could be changed. This could lead to some confusing edge cases (what happens when you later change the formatting of the original? Probably the new lookup remains unchanged).