“It should be put to gedolei ha-dor and see what they say to do. They are our eyes and ears.”
I think if there were a genuine threat,that people have to use their own seichel, and not rely on the opinions of others. Many of our gedolim of Europe kept telling people to stay put as Hitler Y”S came to power, and we lost a significant number of Jews who could have otherwise been saved had they NOT listened to those rabbonim and instead had run to E”Y or America. With respect, not every issue is a rabbinic one.