Kick out garrisons when city is destroyed

[Roop]

I'm still new at this game, so correct me if I'm wrong, but I think that if ships are in harbor and the associated city is destroyed, all the units are erased.  Same goes for units in a military zone.  I think that destruction of city should kick out all units from the naval yard, and mil zone's airfields and barracks should do the same for their respective units, before saying 'associated city is destroyed'.