- it would in a smuch as it 'notifies' the filed alternate and gives them the right to refuse the FP if circumstances pertain? I did say it was pedantry
Hmm- I don't think you'd bother filing the aerodrome as an alternate, as it doesn;t fill any regulatory requirement for the carridge of an alternate. That wouldn't stop you doing an in-flight amendment and diveting to said aerodrome, but it would be a change of destination, not a divertion to alternate.
So using my scenario, the airport must be open till 1130pm correct?
Correct. A destination alternate is somewhere you can go to if you divert from MAP. If it's closed, you can't.