It should be relatively easy to confine them to their quarters and a shrine. They're being transported as pilgrims, not combat advisors or sightseers. There's no reason they should be allowed free run of the ship. And for the Guard veterans, that should be what they're used to. I don't believe Guardsmen are normally allowed to wander Navy ships as they wish. Bad for morale, can lead to inter-service brawls, that sort of thing.