There is a sign outside a shop near us which says 'Parking for loading vehicles only from 7 to 12pm'. Does that mean between 7pm and midnight, or between 7am and noon?
For me 12.00 is neither post-meridian nor ante-meridian, it is either noon or midnight.
Equally when someone says from midnight on the 3rd, do they mean midnight which precedes the 3rd or midnight which ends the 3rd. The precise moment of midnight belongs neither to one day nor the other.
These are crucially important matters as regards flight timetables, and insurance policies. If the policy expires at midnight on the 15th, when exactly is that? It is why many insurance companies now speak of 12.01am on the 22nd or 11.59pm on the 21st.
Should it be insisted that all references to 12.00 state either noon or midnight and how can we express midnight with clarity?