They'd not experience this situation as, like another commenter stated, even a pyrex glass has nucleation sites for boiling

If they've double-microwaved the water then they have a chance at superheating, but that is not the same situation as just microwaving water in a pyrex cup, the thing that was being called extremely dangerous

But sure, well just keep being scared of doing it at all because some people can't remember that they already heated something