More on Q-ships:
Frequently, what you'll find in EVN:UGF is Q-ships owned and operated by Galactic privateers. Privateers are what I disparagingly refer to as "pirates with papers." They get a license from a given government that says they can hunt down ships of opposing factions. The UGF is well known for using every tool and tactic at its disposal in wartime (short of deliberately attacking civilians, biological warfare, destroying planets and environments, and the like), and regularly licenses privateers to go after enemy shipping (which the UGF terms "economic warfare").
Galactic privateers receive auxiliary ranks in the UGN, a decent paycheck, and the right to supplement their income by selling off captured starships and cargoes, tax-free. There are limitations on them, however. First, while not direct members of the UGN, their Navy rank means they are required to obey lawful orders from superior officers. Second, privateers may not attack allied vessels. Ever. Privately owned ships are off-limits too: only government cargoes and vessels may be attacked, except in defense of oneself or of innocents (a primary function of the privateering program is to assist the UGN in combating piracy). Failure to abide by these rules means the loss of one's license, no second chances, and frequently court martial as well. Also, one man's privateer is another's pirate: treatment of captured Galactic privateers varies from government to government, and while the Axe-tails accord them POW rights, the Balcrusians are not shy about spacing them.
One of the most notorious cases of privateers going bad is Yapeel, a Paz/kanran. He was stripped of his license and court-martialed for robbing a pharmaceutical shipment within Galactic space. (The Navy Criminal Investigation Service (NCIS) investigation threw suspicion on a Republic Group subsidiary for hiring Yapeel to do their dirty work to a competitor, but nothing ever stuck.) Yapeel broke out before sentencing, stole a Foxfire and fled Galactic space. He now heads a full-fledged pirate faction, the Vibroaxe Death Knights; the UGF has a bounty of 400,000 credits for him, dead or alive.
In case you're wondering, I'm trying to go for a hopeful, but gritty feel with EVN:UGF. I don't know if I'm going to make "Galactic privateer" a career path (might not have enough room in the TC, and privateers can't get Navy ships), but it's one of the elements of the story.