common, was this Rav in your community, or was he a 5-town Rav who decided to pasken in your community? I would say if he is a Rav in your community, he has a right to do so and you should listen. If he is a visitor, not clear what his authority is.
It also depends on what the government rules were at the time and place. As I mentioned before, R Henneman advocated super-careful compliance with the early decrees of no-minyanim-in-the-yard. I do not know what was his position later on.