The Traders' Guild is the biggest cargo transporting company by far, constantly moving stuff around the planet. They not only maintain their own supply chain, but also take a lot of government contracts for moving the least-to-moderately important stuff. So many Freighters are operating at once that the Guild cannot protect them all, and they're not very well armed themselves, so consider them fair game! Just think about all the expensive stuff inside, waiting for us. Freighters have moderately big crews, but they're mostly weak and cowardly, so we should just capture and sell them. However, Freighters rarely land in the wilderness, so we need to shoot them down else they'll land in cities, out of our reach.