Whoever supplies the navigation data for the hyperdrives ultimately controls where we can go. We have a complete map of all the targetable jump destinations in our ships. It's just a "software" change in the hyperdrives to disallow travel to certain locations.
It just occurred to me that this could be used in the BGS as a possible failed outcome of an disease outbreak. The system could be quarantined, and no ships permitted to travel there. Then, when the quarantine is lifted, the population of the system could be less, and the economy could be changed (fallen from hi-tech to agrculture, for example)