All the talk about Force Majeures getting in the way of successfully completing a landing at an alternate, with min fuel and no other escape etc. etc. seems to be without regard for the fact that, if the crew declare an emergency or for any justifiable reason (only to be justified AFTER the fact) deem it necessary to bust the minima, then they cannot be stopped from doing so.
Rules are rules but not even regulators want to see you turned into a smouldering pile of wreckage just because you couldn't get visual at the minima IN AN EMERGENCY!!!! They'd have to fill out too much paperwork!